Playlist improvements

[fredg02]

First of all: Thanks for the Clementine Android-Remote! It has the potential to be a simple yet powerful remote application. :)

Here are a few ideas how the playlist handling could be improved.

• I second the request to have a "Clear playlist" button (see Issue 75)
• Deleting multiple songs from a playlist takes an awful long time, because the user has to "long touch" every song and delete it. So a multi-selection mode (similar to the one in the standard Android gallery app) would be nice. It could be activated from a menu in the top right corner.
• Simple "swipe-to-delete-a-song-from-the-playlist" mode (maybe with an undo functionality)
• Also easy re-arrangement of songs in the playlist would be nice (multi-selection as a bonus)
• layout improvements: smaller track number, overall less padding
• option to activate smart playlist modes (e.g. 50 random tracks, dynamic random mix, etc.)
• load/save a playlist from your Android device
• synchronize playlists with Clementine desktop application

The list might need to be split up into individual tasks, I just did not want to spam the issue list. I will try to find time to help with some of the suggested tasks.