implemented gauss_beam function for gaussian beam transfer functions
improved docstring of gauss_beam
prepare for switch to Healpix 3.0
Merge branch 'master' of github.com:healpy/healpy
Revert "prepare for switch to Healpix 3.0"

This reverts commit 1a76098ec73a66f5f33647e7764cbceea30eccfd.
removed psht and pshyt
renamed boundary to boundaries
added libsharp to linking
renamed boundary to boundaries and removed obsolete tests
import boundaries to root namespace
now healpix is added as git submodule
pointed healpix to branch healpy with fix in libcfitsio include flags
write_map more flexible, accepts list of column names
removed previous healpix submodule
added new submodule for healpix
moved submodule to healpy branch
moved path to new submodule
moved to master branch of the healpix submodule, as @mreineck added a fix upstream
removed cpp files generated by cython
added warning if healpix folder is empty