Removed unused channel file. Updated HISTORY.
Changes in Main Menu buttons positioning and gfx.

Change: Removed [Credits] button in main menu. 
Change: Added button hover image.
Change: Button text no longer changes on hover.
Text html syntax fix in main screen.
Fixed caching of scripts when loaded by RequireJS. This required the
RequireJS to be configued to load scripts with version param generated
in the index.php.
Game sfx loading enabled. Game timer reset to 180 mins. Removed FPS
view.
Added build folder to contain game build.
Removed playatomic lib. Unused.
Added build folder to .gitignore.
Added build script and YUI compressor.