added the swipe-to-dismiss lib
added the delete playlist feature.
improved SongListActivity
Fixed bugs. Added Adding songs to a playlist functionality
Finished Shuffle and Repeat
Finished the initial version of Adding and Removing a song from a playlist.
Fixed the position bug
Added UI margin
Used Future to load songs: non-block
smooooooothed out the listview.
optimized: added cache and shrank bitmap
removed while loop
cleaning up
git rm and ignore some folders
git rm unused files
fixed CalledFromWrongThreadException
Updated README
Another clean-up
fixed the back button bug
fixed manage playlist bugs