[Mesa-dev] i965: no more regions!

[Eric Anholt]

Here's the series for removing struct intel_region from the i965 driver.
I think it's worth it for the code savings and reduced steps in allocating
a miptree.  Plus, it gave me a chance to rewrite some comments about the
driver.

It's a longer series than I wanted, but there are some nice little
cleanups in it that hopefully make it easier to review than 18 patches
would usually be.