[yt-users] Changes to the trunk

[Matthew Turk]

Hi there,

Tonight I'm merging a bunch of changes from me, Britton Smith, John
Wise and Stephen Skory back into the trunk from the mercurial
repository.  If you're running on the yt-1.5 source tree, this won't
affect you -- but if you're running on trunk, the next time you update
you will have to rerun "python2.6 setup.py develop" or "python2.6
setup.py install" depending on how you installed.  If you used the
install script, you should also be able to re-run it at any time to
get an updated source tree and installation.

There are no pressing fixes in this, only speed and memory
improvements, so don't feel it's necessary to make the jump just now
if you're happy with where you are.  If you do update, here's a minor
changelog:

 * Hierarchy is much faster, and the .yt file now only stores data
products, all hierarchy info goes into a .harrays file (for forward
compatibility with Enzo)
 * The attributes off the hierarchy for grids: gridLeftEdge and
gridRightEdge are now grid_left_edge and grid_right_edge, in keeping
with our coding standards
 * Hierarchy has been rewritten for *clarity*
 * The bug with DM-only sims has been fixed
 * IO routines have been refactored and very cleaned up
 * Preliminary particle IO readers have been added -- much, much
faster, but not yet production-ready
 * New cloud-in-cell deposit function without needing fortran
 * Some other minor things to support coming features

All the public and primary functions, classes etc should be the same.

Thanks, and let us know if there are ANY problems!

-Matt