fixed playFrom() crash, support queueing entire row (eg: last played)

[mueslimak3r]

Changes

• fixed crash when calling playFrom() where the player was unintentionally released
• clicking on an audio item will now:

• open NowPlayingActivity if it is the currently playing item
• use playFrom() to skip within the queue (and not affect things like shufffle, etc) if the item belongs to the queue
• otherwise, start a new session by adding the items in the row to the queue and playing from the selected item's index. This means we can easily play all "last played" songs

• playNow() will loop through its input list and create a new list of only audio items. This protects against accidentally adding video items if an entire row is added to the queue. I don't know of any rows that have mixed A/V items but better safe than sorry, and the methods for adding to the video queue already do this.

• changed deprecated mExoPlayer.stop(boolean) -> mExoPlayer.stop()

Issues

• the audio player was being released unintentionally
• playFrom() in the context menu was missing a return statement, which caused some weird behavior