[Yt-dev] Stage two of branch consolidation

[Matthew Turk]

Hi again,

I've consolidated the yt and memory-optimization branches in the yt
repo in mercurial.  If you want to use either before this merger, the
last changeset hashes before the merger are:

97e2160d876b (memory-optimization)
ab99adbbe406 (yt)

The new 'yt' branch now contains the massively parallel halo finder
from Stephen Skory, as well as a fully rewritten hierarchy class.
This will become the new dev trunk relatively soon.  If you are
concerned about changes in it, please clone it and test it.  There
were two bugs I was notified of in the svn trunk after last night's
merger that I have now fixed.

If you find a problem in this branch, you can either fix it or add it
as a unit test to tests/test_*.py.

-Matt