basic layout for SongsList widget
rebased on top of current master
added playlists.py to makefile
added dialog for playlists selection.
added playlistdialog.ui
Some Add to Playlist Dialog cleanup

- Move some of the code into the ui file
- Fixed the renderer that doesn't show up
- Add missing window decorations
- Some code refactoring
Start editing New Playlist item on single click
Cleanup class ordering
view: Add songs list view to Playlists view
grilo: Check for grilo filesystem plugin
grilo: Add method to get a media object from uri
playlists: Add new method for getting path to a playlist
playlists: Add method for parsing playlists
grilo: Connect signals to registry first before loading plugins
playlists: Skip unexistent files
view: Load songs of playlist when selected
view: Monitor playlist songs
view: Update model when current track changes
grilo: Use synchronous get_media_from_uri

The async one causes segmentation faults.
view: Play song when activated