Change parsing of metadata to follow the Flash Player, and return deep clones with public names when requesting it via DescribeTypeJSON
Speed up Interface#IsInterface check by turning cls.implementedInterfaces into a map with the interfaces the class implements as keys (and values)

Theoretically, the lookup should've been a linear search through the class's list of implemented interfaces. Because of a bug in applyInterfaceBindings, it was a recursive search through all of the class's parents' lists, which contained duplicate entries for their implemented interfaces: one for each child class ...
Merge pull request #240 from tschneidereit/master

Some fixes to reflection stuff. r=mbx,jeffdyer