Added SRS transformations to geotrellis.util.srs

-Added two Spatial Reference Systems (SRS), Web Mercator and Lat Long, and the transformations between them.
-Removed geotools dependency from geotrellis-server, the only thing being used for this was the reprojection capabilities of geotools. (Closes #567)

NOTE: Anything using the geotrellis.admin.Reproject object will now need to use the new method.