Update distribute_setup.py to 0.6.44
Closes 1752. Patch3DCollection can now be empty.

Also improved the Patch3DCollection constructor.
Added labels to images in the gallery

- Right now it's just the filename of the example
- It should perhaps be a string that we define in the example file
  (like in scikits-image / scikits-learn)
Merge pull request #2130 from mdboom/distribute-to-setuptools2

Update distribute_setup.py to 0.6.44
Merge remote-tracking branch 'upstream/v1.3.x'
This commented-out code seems unnecessary.
Merge pull request #2168 from katyhuff/minor_cleanup

This commented-out code seems unnecessary.
On Python 3.3, the __loader__ variable may get set when modules are loaded, so this is ok to override
Merge pull request #2161 from tbekolay/better-gallery

Added labels to images in the gallery [sprint]
Merge pull request #2170 from mdboom/overriding_loader_is_ok

overriding "__loader__" is ok
Just a minor comment tweak

Documenting where to add titles to figures in the gallery should we choose to
do that.
Merge pull request #2174 from dmcdougall/comment_tweak

Just a minor comment tweak
Merge pull request #2162 from WeatherGod/mplot3d/empty_patch3dcollection

[SPRINT] Closes #1752. Patch3DCollection can now be empty.