Added noImages and compactMode prefs

Implemented as persistent cookies via Env methods. Added
jquery.cookie.js to facilitate managing them.

Used to hide images on the game page and to put the page into compact
mode, respectively.
Merge remote-tracking branch 'upstream/master' into 528_noImage_compactMode_prefs
Split accessors and prefs sections, fixed tests
Removed *'s and added blurbs
Merge pull request #851 from AdmiralJota/528_noImage_compactMode_prefs

Preferences to turn off button images and make the battlemat compact
Merge remote-tracking branch 'upstream/master'