Post-processing infrastructure
* remove interfaces with one implementation
* fix download resources with unknow length
* marquee style for ProgressDrawable
* "view details" option in mission context menu
* notification for finished downloads
* postprocessing infrastructure: sub-missions, circular file, layers for layers of abstractions for Java IO streams
* Mp4 muxing (only DASH brand)
* WebM muxing
* Captions downloading
* alert dialog for overwrite existing downloads finished or not.
Misc changes
* delete SQLiteDownloadDataSource.java
* delete DownloadMissionSQLiteHelper.java
* implement Localization from #114
Misc fixes (this branch)
* restore old mission listeners variables. Prevents registered listeners get de-referenced on low-end devices
* DownloadManagerService.checkForRunningMission() now return false if the mission has a error.
* use Intent.FLAG_ACTIVITY_NEW_TASK when launching an activity from gigaget threads (apparently it is required in old versions of android)
More changes
* proper error handling "infrastructure"
* queue instead of multiple downloads
* move serialized pending downloads (.giga files) to app data
* stop downloads when swicthing to mobile network (never works, see 2nd point)
* save the thread count for next downloads
* a lot of incoherences fixed
* delete DownloadManagerTest.java (too many changes to keep this file updated)
-Added LeakCanary as part of debug build.
-Modified bookmark list to show both remote and local playlists.
-Removed ability to save channel items as local playlist, in favor of subscribe.
-Added selected item bullet.
-Modified play queue panel darker on main video player.
-Fixed color issue on play queue panel on light-themed main video player.
-Fixed hold-to-enqueue tooltip flashing when clicked on earlier sdk versions.
-Fixed queue item removal causing metadata for currently playing to refresh.
-Added icons for shuffle and drag handle.
-Fixed exception when returning to background player activity after service shuts down.
-Fixed open detail only working for Youtube.
