Magma on Cog - initial test

Well, I still need to do more testing, but so far Cog looks to be
Christmas in June!

The Magma tests suite passed, and in 20 minutes (vs. 37), I'll add.

I've also updated the Magma benchmark page with just an initial run of
the local benchmarks.

  http://wiki.squeak.org/squeak/5606

The old numbers are under "Local" and the new numbers are under "Local
with Cog" (open two browsers side-by-side to easily compare the #'s).

In summary:

  - Read performance is increased roughly 4X across the board
  - Write performance with Cog, but without WriteBarrier is even
faster than the old VM with WriteBarrier.
  - Bulk-load test seems to be about 2-3X faster.

Maui and other morphic widgets are blazing fast.  Dragging and
animation seem to be much smoother.

It's wonderful!

 - Chris