Bug 44855, Bug 37743: Improved vector button styles for jquery.ui

Removed the orange because orange is an evil colour, made the other colours
brighter with softer gradients, added specific support for active and focus
states, made disabled buttons all grey.

Looks like this: http://jsfiddle.net/vPaM2/12/

Bug: 44855
Bug: 37743
Change-Id: I6f28ce6c9c3403d8377b4b3aaa7495b01853ee0e
Merge "Bug 44855, Bug 37743: Improved vector button styles for jquery.ui"