Fix a potential NPE.
Use consistent fonts in now_playing_fragment_*.xml.

Remove bold styling, and use the @style/SqueezerTextItem where appropriate.
Support play/pause from the now_playing_fragment_mini layout.
Fix items not loading after resume from sub-activity

Responses which come in after callbacks have been unregistered are discarded,
but they are marked as ordered, so they are are not reordered when a view is
requested.
We cancel outstanding orders after unregistering callbacks to solve this.
Correctly unregister songlist callback

This fixes a potential activity leak, cause the service keeps a reference to
the callback, which holds a reference to the activity.
Enable Android Studio and the Gradle build system

Ignore workspace files and add gradle build files.
The project can be imported into Android Studio using gradle.build.
Cleanup and polish SqueezerBaseListActivity

- SqueezerBaseListActvity: Initialize image fetcher on demand, so it can be
  used before onCreate is called.
- Do not leak pages when items are reordered, and prevent previous items from
  showing briefly.
Update the UI on return from browsing songs of a playlist

Use startActivity for result to start the child activity, and update the list
with any changes, in onActivityResult in the parent activity
Merge branch 'actionbar' of github.com:kaaholst/android-squeezer into actionbar