Merge pull request #45 from jjhelmus/master

Working RslDisplay and clean up of other rsl related files
Merge pull request #46 from jjhelmus/master

Updated and documented Cython wrapped around RSL and FourDD algoriths
changed permissions on os/src/patch_and_make.sh
Merge branch 'master' of https://github.com/ARM-DOE/pyart

fixed permissions on io/src/patch_and_make.sh
Merge pull request #47 from jjhelmus/master

ENH : map_to_grid function

The map_to_grid function created a Cartesian map from one or more radar objects.

* can use either a k-d tree or ball tree for fast neighbor lookup.
* documentation and tests included.
* support for mapping multiple radar untested and known broken if copy_field_data = False, this will be fixed next week.
Merge pull request #48 from vanandel/master

patch_and_make.sh - make executable