change hpbeta to healpixsubmodule/src/cxx in MANIFEST.in, to include healpix cxx in the source distribution (made using 'python setup.py sdist')
remove unused pshyt.pyx and pshyt.c (since moved to libsharp)
remove unused test_pshyt.py (since use of libsharp)
changed hpbeta to new folders in INSTALL, closes #85
add requirement of cython .16, previous versions cannot compile the latest version of the extension. closes #87