Merge branch 'imapsearch'

* imapsearch:
  Change settings version to 18 to match what's currrently on master.
  Handle aborted imap searches by nuking in-progress connections.
  Move IMAP search into the Folder level.
  Remove duplicate notification on remote search start.
  Rename variables
  changed PREFERENCE_CLOUD_SEARCH_ENABLED from "cloud_search_enabled" to "remote_search_enabled" in activity/setup/AccountSettings.java to resolve FC.
  Add cloud search icon to local search result screen. Implement pull-to-remote-search.
  Log remote search exceptions in addition to toasting them.
  Add settings export for remote search settings.
  Whitespace; no functional changes.
  Handle implicit vs. explicit searches in ActionBar home button behavior.
  Whitespace fix; no functional changes.
  Add remote search actionbar icons.
  IMAP Search: log exceptions on remote search, properly dispatch MessageList changes.
  modified loadMessageForView() to dowload message if neither X_DOWNLOADED_FULL nor X_DOWNLOADED_PARTIAL.
  Add remote IMAP search support.

Conflicts:
	res/menu/message_list_option.xml
	res/values/attrs.xml
	res/values/themes.xml
	src/com/fsck/k9/activity/MessageList.java
	src/com/fsck/k9/preferences/Settings.java