Merge changes from topic "fdevent_refactor"

* changes:
  adb: fdevent: extract Add/Del/SetTimeout.
  adb: fdevent: extract Create/Destroy from fdevent_context_poll.
  adb: fdevent: move TerminateLoop to fdevent_context.
  adb: fdevent: move CheckMainThread logic to fdevent_context.
  adb: fdevent: delete FDE_CREATED.
  adb: fdevent: move run queue to fdevent_context.
  adb: implement fdevent_reset by constructing a new context.
  adb: move fdevent implementation out to a separate file.
  adb: de-globalize fdevent context.
  adb: move fdevent to its own folder.
  adb: add superfluous include.