Change flash.utils.getTimer()'s startup timestamp to when the first SWF's first frame is committed

This aligns much more closely with what the Flash Player does.
Delay AVM1 MovieClipLoader's INIT event by one frame

According to gospel, this is how it is done.
Add reftest for AVM1 MovieClipLoader
Merge pull request #1755 from tschneidereit/loader

More AVM1 MovieClipLoader fixes
Enable specifying tests to run with `grunt exec:test_avm2`

Only works for single tests for now, though.
Changed lots of Array methods to use browsers' builtin implementations

Reduces complexity and code size and shaves off about 30ms of startup time.
Merge pull request #1756 from tschneidereit/loader

Native-ify various Array methods
Remove AS3 implementation of Array constructor

Because it's functionally identical with the JS one. Another 10ms of startup time win.
Merge pull request #1757 from tschneidereit/master

Remove AS3 implementation of Array constructor
Differentiate profiler timelines for memoized and non-memoized method binding application
Optimize method trait trampolining to get rid of one closure

Reduces memory usage and improves performance of both creating and executing the trampolines.
Merge pull request #1758 from tschneidereit/master

Trampolining optimizations