Version codes of releases (master builds) are now always higher than version codes of beta builds (feature branches).
This ensures we can always update the production release.

* Introduce composable TaskAction handlers
* Implement TaskActions required for feature parity with the old service
* Clean up old notification services

This commit adds a read-only task VERSION column which is incremented upon any update or a task (including sync-adapter updates).

The column serves two purposes:

* safe transactions by asserting a specific version before updating a task
* quick detection if a specific task has been modified

The former could be used by sync-adapters to ensure a task has not been updated while being synced.
Notifications will make use of the latter to avoid unnecessary updates of task notifications for unchanged tasks.

Reduces/removes lag while background sync (#738)
Also avoids reloading widget multiple times after a change to a task.

In addition to just updating the ContentPal version this also replaces usages of deprecated jems classes.

In order to evaluate the provider performance and its impact on the UX this commit adds some simple profiling statments which measure the execution time of certain operations and write them to logcat.
Hopefully this helps a but to detect slow operations and bottlenecks.

Instead of creating the details view lazily when the task is loaded, we create it in `onCreateView` so it always exist. Hopefully this fixes #755, but since the actual reason is still unclear we can't be sure. In any case the details view needs a refactoring which reduces mutable state and makes it more robust.

Under certain conditions the task details fragment was about to be replaced after the fragment manager already saved its state. This caused a crash. This change checks whether the state has already been saved before committing the transaction.

The previous implementation tried to use the CONFLICT_IGNORE policy when inserting new ngrams and was falling back to a query in case it failed to find the id of the exiting ngram. This was very slow because it meant an expensive query for every ngram to insert.

The new solution goes over the existing ngrams and only inserts the ones which don't exist in the database. Similarily the ngram relations table is not cleared for the particular task, instead the existing ngrams are loaded and only new relations are inserted and obsolete relations are removed.

* fix recursive updateNotification calls
* replace compile with implementation

This commit removes the changelog we've sent with the ProviderChanged Broadcast. It's never really been used so far but may blow the IPC buffer size limit.
We need to find a better way to communicate changes efficiently to plugins once we support them. It's not a pressing concern though.

The regular expression for the internal track didn't cover a revision descirption like `1.1.16-dirty` which is a release commit with changes.
The proposed fix makes the part between the version number and `-dirty` optional.

This commit adds a workaround for sync apps which don't grant account visibility to OpenTasks. If a task list is inserted which belongs to an account which we can't see, the app asks for permission to see the account.
The `GET_ACCOUNTS` permission is no longer used on Android 8+ and the request for that permission will no longer be shown when the app starts.

Update the publish configuration to derive the publishing track form the version number.

In an earlier commit we changed how the lists are loaded. Instead of loading them from the tasks table we now load them from the instances table. This was meant to prepare support for recurring tasks.

Unfortunately we missed on line where we were still using the `_id` column to get the task id (when we should actually use the `task_id` column now). This didn't cause any problem as long as the task id and the instance id where in sync (hence it wasn't an issue while testing). However, under certain circumstances this assumption is no longer true and caused an illegal Task URI to be loaded when clicking a task.

The list now uses the `task_id` column to create the task URI to show.

This adds a plugin which allows for publishing the app autimatically to Google Play.

Adds an optional signing config, which is ignored if no keystore property is present.

This also updates the support library version to 26.1.0.
Due to changes in Android 8 we had to limit some background service and broadcast functionality. There are no limitations to the user experience though, but some planned features may require a different solution now (mostly because implicit broadcasts no longer work).

Commit 5f4e9012 contains a couple of changes which break the UI in that some elements don't respond to clicks anymore.
In particular the `focusable="true"` attribute seems to cause these issues. For now we simply revert the addition of these attributes.
In another story we should address the issue and fix the layout.

This commit switches from using the color picker as an activity via the open intent to using the color picker as a dialog fragment. This means the color picker is fixed now and no external picker can be used. It's not clear if anyone actually did that though.

This adds adaptive icons for Android 8 and round icons for older Android versions which use them.
Also the bitmap icons are now moved from drawable to mipmap.

This solution fixes a number of actual and potential bugs around changing the content of the details pane. The view fragment can be simplified further. That's subject to another story.

javadoc fixes and more

* android lint (accessibility - performance)
* Keyboard inaccessible widget
* ScrollView size
* Use apply() on SharedPreferences
* Obsolete layout params
* android lint (security - code style)
* showAsAction=ifRoom
* code style issues

This commit adds a permission group for tasks. The permission group has a dediciated description which, for most languages, is derived from the write permission description.

@native speakers, please feel free to update these and bring them in line with the default translation.

Improved german translation.

Commit new code style settings file introduce in Idea 2017.3 (Android Studio 3.1 automatically generated these files, migrating the project rules from the old format). #671 (#672)

Use View.peformHapticFeedback() instead of Vibrator.vibrate() for list item long press and checklist long presses so it is enabled/disabled as per device settings. Remove an unused field in FlingDetector. #191 (#660)