Add polygon method stubs.
Use an enum for geometry types, plus changes to subclass init methods.
Merge and update to enum geometry type.
Update geometry factory method.
More stubs for polygon.
Expose geoJSONStringForType and geometryTypeForString.
Rename TFGeometryType to TFPrimitiveType.
Add enums for feature, feature collection.
We need a shared scheme to run a bot.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	Terraformer.xcodeproj/project.pbxproj
	Terraformer/TFFeature.h
	Terraformer/TFFeature.m
Merge pull request #11 from mbcharbonneau/master

Change geometry type to an enum, factory method on TFGeometry to instantiate subclasses.