Added VerticalFlip global method.
Broke out each global spark op to an individual object, since they get quite big. Working on the distributed cost-distance, currently trying to use GraphX for multiple-source shortest path.
Added a graph package for dealing with graph stuff. Currently writing test code for creating a raster from a graph.
Turning a cost-distance raster into a GraphX graph is now implemented and tested.
Added graph to raster method, which is both implemented and tested. Also added initial implementation of multi-source shortest path taken from GraphX source code (but with distance at edges).
Multi Source Cost Distance works and tested. Though think I have found a bug in single cost distance.
Merge pull request #935 from johanstenberg92/global-ops-spark

Global Operations Spark + GraphX Integration