Merge pull request #326 from avuton/master

Add a few useful input type hints to the connection settings windows
Fix #327 : List cover art progress bar spins forever
- Cover progress bar display is now triggered by the message "onCoverDownloadStarted" sent by the cover manager.
- The cover is then displayed by the album cover listener when it receives the onCoverDownloadStarted message.
- The cover manager sends the onCoverDownloadStarted message when the cover is downloaded from the web (no progress bar when the cover comes from the cache)
Improve cover fetching speed
Factorize cover download requests even if their priorities are different.
Allows to factorize requests from the nowplaying fragment (high priority) and from the playlist (normal priority)
Always show fast scroll for 4.4

Workaround for fast scroll not being visible on 4.4 devices.
Merge pull request #333 from ssmy/master

Always show fast scroll for 4.4
Fix titlebar when back is pressed. Fixes #332
Global album list is never a grid
Grid view is now the default view
Minor improvement for AlbumInfo
- Use the AlbumInfo check in the cover manager.
- Simplify getKey()
Improve cover request robustness : Let the cover manager triggers the cover view tag with the album key.
Avoid the use of a different album key to tag the view (in case of album key mismatch the cover notifications are ignored by the cover listeners)
Revert "Improve cover request robustness : Let the cover manager triggers the cover view tag with the album key."

This reverts commit 9555f3ecd51d9d80d49e0cf959668d13e9e4caa8.
Identify invalid albumInfo (missing artist or album) with a special tag instead of NULL.
-> Allow them to avoid receiving wrong cover notifications
-> Fix the case where you reset the cover (blank one) from the nowplaying fragment but the cover in the playlist was not refreshed.
Fix playlist cover update when changing cover from the nowplaying screen
In some cases the playlist cover was not updated (when the playlist cover is not visible when the cover download notification happens)
Add a tag to force (just once) the cover refresh when the List getView() is called.
Fix playlist cover update when changing cover from the nowplaying screen
--> Clean the code by putting the refresh informations in the model instead of adding a new cover tag.
Avoid crash (NPE) when using filter on items without album (radio streams ...)
When updating playlist cover (blacklist or rest) do not display no_cover_art
+ Minor refactoring :
- updateCover now uses albumInfo
Increase cover download priority for songsfragment (album view)
Refactor PlayListMusic: Replace delegation with inheritance to simplify code.
Rotation now works as expected in MainMenu and SimpleLibrary. Fixes #336
Refactored ArrayIndexerDataBinder into ArrayDataBinder