GEOMESA-221 Create encoding for SFTs that includes index toggle

Added a utility class for working with SimpleFeatureTypes.

Upgraded specs2.
Oh!  I missed that this is the Java documentation test.  

Given that the OSM features have :'s which cause issues for GT DataUtilities's createType, I'd suggest adding a Java wrapper to access SimpleFeatureTypes.  That can happen later if it is deemed a good idea.