HEALPix submodule updated

HEALPix C++ sources updated from SVN until commits on 27 Sep:
6d4750c96561fbaf78de1f4fd6c251cb68e80736
typo in doctest of hp.boundaries, #115
recent version of matplotlib in requirements
vectorize boundaries()
put some protection against too large pixel values in boundaries()
otherwise FPE is generated
Fixed pix2ang docstring, #131
More consistent nside validity check

created new function `check_nside` that throws exception
if `nside` is not valid, now this function is called in
any `pixelfunc` function that uses the `nside` parameter.
Closes #131.
fixed doctests in pixelfunc, run doctests on travis
matplotlib 1.2.1 for python 2.5 compatibility
added script to run cython doctests, #130
Temporarily disable python 2.5 travis builds

Python 2.5 cannot build matplotlib 1.2.1, so it fails,
need to fix this, in the meantime python 2.5 test is disabled
run doctests and doctests/cython on travis
typo in travis testing script
unit of colatitudes in docstring
support for verbose keyword in spherical armonic functions
moved mask zero-filling in anafast after monopole removal, closes #132
added orthview function and nose tests
a few additions to .gitignore
return orthview projected map correctly, fix mask out-of-range values
Merge pull request #133 from arahlin/master

Orthview, closes #121