Add option to tweak animation speeds

Response to feature request http://forum.dominionstrategy.com/index.php?topic=8163.msg354906#msg354906.

Adds two options that tweak Goko's default animation speds:
* speed_tweak_uniform: For the most part, "fast" is 2x the speed of "medium" and "veryFast" is 8x, but there are exceptions, including the purchase delay that  sudgy refers to.  This option applies the 2x and 8x factors to all speeds uniformly
* speed_tweak_faster: This makes "medium" and "fast" modes each about 50% faster.

Implementated by simply changing the values in Dom.GlobalLayout.animationTimings.