Many changes in used libraries

* added new spectrum color picker by bgrins
* added twitter bootstrap
* added pusher color library
* removed jPicker color picker
* removed jquery-ui
design changes
New style for preview boxes
Even better color style for preview boxes
Design changes for color history
Added font awesome
Small cleanup
Renamed bg to bgPage to avoid confusion
Remove option to disable color picker
Change history clearing, colors and message passing

History clearing is now done in bg script so it is more consistent
Last color from history is now used on extension init
Default color is used when no history
Message passing from popup now fixed
Update of credits page
Color picker design changes
Fix default color setting for picker
Fix yellow border around first tab
Fix of button display on color picker
Change of disabled pickup message display
CSS cleanup
New design for options page