Bug 728629 - canvas2D fillText & strokeText do not throw exceptions when non-finite doubles are passed for the position. r=vlad
Bug 904701 - Implement prototype madness for ES6 generators. r=bhackett, r=jorendorff

Add a Generator constructor, like the Function constructor.

Define the GeneratorFunctionPrototype, GeneratorFunction, and
GeneratorObjectPrototype meta-objects.

When cloning or creating a star generator, give it
GeneratorFunctionPrototype as its prototype.

Each star generator function has a ".prototype" property, which has
GeneratorObjectPrototype as its prototype.  That prototype does not have
a ".constructor" link.

If Function.prototype.toSource is called on a non-function, chain up to
Object.prototype.toSource instead.

Prototypes of generator objects are no longer made with
GeneratorObject::class_.  This allows us to elide some "null" checks
from bug 352885.  Instead calling a generator on a method now signals a
typeerror.

Make the "send" generator method a simple alias to "next".
Bug 906773 - More efficient ComputeSliceBounds function. r=nmatsakis
Bug 907816 - GetCSSValuesForProperty does not use the display keyword table. r=bz