Change "typedef" to "class" in core library and related tests.

Change "typedef" to "class" in core library and related tests.

R=floitsch@google.com, johnniwinther@google.com

Committed: https://code.google.com/p/dart/source/detail?r=28712

[Lasse Reichstein Nielsen, 2013-10-15 08:28:38]

Blocked on datbug.com/13907

[floitsch, 2013-10-15 08:56:36]

LGTM.

[hausner, 2013-10-15 16:16:21]

I just checked in the VM change. You may have to update a couple of tests that I
had already converted as part of my change.

[Lasse Reichstein Nielsen, 2013-10-16 08:36:08]

Excellent. 
I changed the dart2js unparser. Johnni, please check it (just the last patch).

[Johnni Winther, 2013-10-16 08:52:24]

dart2js changes LGTM

[Lasse Reichstein Nielsen, 2013-10-16 09:03:23]

Committed patchset #4 manually as r28712 (presubmit successful).