Replace distribute_setup.py with the latest ez_setup.py for setuptools 0.9.x.  Moved all the boilerplate for checking how to boostrap setuptools into a new module alongside setup.py called setuptools_boostrap.py, just to hide some of the ugliness contained therein.  It should be noted that with the latest version of ez_setup.py, as setuptools can't be used to upgrade itself, users with an outdated version of setuptools will be admonished to first uninstall their old setuptools.  This could be tricky if they get their setuptools from an OS system package.  But I would tell anyone with that old of a Python installation to either install their own Python distribution or use virtualenv.
Adding some notes to the installation troubleshooting regarding the implications of having an outdated setuptools.
Remove bounds from Angle class
Add Angle.wrap_at() method and tests
Add Angle.within_bounds() + small fix to Angle.wrap_at()
Improve angle arithmetic in hour_angle and lst
Add in_place kwarg to wrap_at()
Add Lat and Lon subclasses of Angle
Fix mistake in calling wrap_at, forgot the in_place arg
Change Lat/Lon to Latitude/Longitude
Add Latitude tests
Add longitude tests
Fix problem wrapping a 0-d Longitude object
Move RA.hour_angle and RA.lst methods to standalone functions
Remove RA and Dec subclasses
Remove useradec and anglebounds from _initialize_latlon()

These two args are no longer needed in the simplified system of
just having Longitude / Latitude classes that function as
RA / Dec, Az / Alt, and L / B respectively.

One notable API change is that Galactic "l" is now in 0 to 360 instead of
-180 to 180.  This required a test change.  From what I can see in
the literature Galactic "l" should be 0 to 360.
Add/update docstrings for Latitude, Longitude, Angle
Update docstring / doctest example for python 2 / 3 compatibility
Update angle docstring examples to not look like doctests
updated link to pynbody web page