JS timeout on Volume change

Behaviour is:
- on change (sliding the knob) => volume is updated every 200ms
- on release => the volume is instantly updated
Make volume knob smoother

Don't refresh GUI knob from real value when it's currently being modified
Incremental updates system

- Remove binary DB file from GIT versioning
- Add DB dump as init sql script
- Add .db in .gitignore
- Auto-run updates through update.py

Update init-db after rebase master

Add minidlna setting

Fix bug update script when running SQL script

Separate modules updates in dedicated file

+ small refactor in update.py
New panel: library

Aiming to display library by Genre/artist/album

Load and display library (WIP)

[WIP] manage library filters

Also change "browse" icon

Lib filtering artist/album/genre

Allow browsing by genre/artist/album

[WIP] library: sort lists, play/enqueue buttons

Fix overlapping divs

With z-index rather than margin, to avoid horizontal scrollbar appears

Library: play, enqueue, play all, enqueue all

Had to hack around when sending MPD commands, due to MPD server apparently not understanding many commands closely sent

Fix closing div unexpected

Library perfs #1

- Don't display all songs by default in library
- Display a button instead to force display all songs

prepare enable/disable library setting

- SQL to insert setting
- Some CSS+JS for enabling/disabling lib
- Reading/writing the setting from DB

Fix double JS inclusion

jquery events were fired twice

Library: always disable on incompatible devices

(That is, when screen is too small)
Also add some information in settings

Several JS fixes

- fixed import JS from PHP (was messed up between settings screen and playback screen)
- fixed missing comma in _messages.en.js
- now library loaded from settings doesn't load the whole library, since it's actually only used in playback mode ; it just updates the tabs
- had to refactor a bit JS function/files to achieve above goals

Library - files refactor

- Files refactor: naming
- Extract lib related stuff to new file volumio.library.js
- Fixed loading issue between playlist and library (now library is loaded only after the playlist is fully loaded, to speed up playlist loading)
- Code cleaning, remove useless comments

Fixed display tab Library in settings

Lazy-loading

- Implement the "loading" part of lazy-loading
- Unloading still needs to be implemented

Lazy-loading

- Manage unloading
- Also remove fixed height lines
Merge pull request #36 from jotak/sq_library

Library + incremental updates
Merge remote-tracking branch 'upstream/master'