Allow packages hosted externally on pip
Update .travis.yml
Update .travis.yml
Test several configuration simultaneously with travis

This rewrite of .travis.yml creates a matrix of eight build
configurations:

- Standard Ubuntu system Python versus Anaconda
- Install from source, or first build an sdist and install with pip
- Use system's external cfitsio library, or build bundled copy of
  cfitsio

Note that it sets `language: c` because the c language buildbot
configuration is a cleaner representation of a typical system. Also,
`language: python` does some very weird things to the system Python
path. Furthermore, this sets us up conveniently to use a Mac buildbot by
setting `language: objective-c` shortly.

Note that when using the system Python interpreter, this particular
configuration retrieves as many packages as possible with `apt-get`.
Merge pull request #161 from lpsinger/travis-matrix-miniconda

Test several configuration simultaneously with travis
Remove no-op

This expression is not assigned to no variable, and so has no effect.
Pass CC/CFLAGS and CC/CXXFLAGS to configure script separately

Addresses #158.
Merge pull request #159 from lpsinger/cflags-parsing

Pass CC/CFLAGS and CC/CXXFLAGS to configure script separately
Release 1.7.4
Update MANIFEST.in

Added CITATION to tarball Closes #165
Implementation of map2alm_spin
Implementation of alm2map_spin
Import alm2map_spin,map2alm_spin in base namespace
Order of the arguments was wrong
reimplementation of angdist
Doctest for angdist
Merge pull request #166 from zonca/angdist

angdist function needs improvements
map2alm_spin and alm2map_spin unit tests

Implemented by Duncan Hanson
* Compare spin-1 alm2map transform to alm2map_der1
* Compare spin-1,2,3 alm2map and map2alm transforms to precomputed
  values for small lmax,nside and spins=1,2,3.
* Compare forward and backward transforms (not very stringent,
  they only agree to ~1.e-2, because healpix is not complete basis).
Restored spin0 test
Fix for spin0

The C++ code assumes arrays are initialized to zero.