Merge pull request #49 from jjhelmus/master

BUG: fixed bug in gridding of multiple radars
Merge pull request #50 from jjhelmus/master

PyGrid refactor
Merge pull request #54 from jjhelmus/master

Merging back in jjhelmus fork
Merge pull request #56 from jjhelmus/master

Py-ART now created CF/Radial compliant netCDF files
ENH: write_netcdf now deals with rank-0 arrays
Merge remote-tracking branch 'origin/master'