Make Polyline and Path use materials

Get rid of most invidual properties and use materials instead
Add PolylineOutline and PolylineGlow materials.
Split Material.jsonschema into two files

PolylineMaterial.jsonschema - Materials applicable to polylines and paths.
Material.jsonschema - materials applicable to everything else.

This has no affect on the resulting CZML, it just makes it impossible to write out a material that is incompatible with it's intended object.
Forgot to save sln.
Merge remote-tracking branch 'origin/master' into polyline-materials
Merge pull request #72 from AnalyticalGraphicsInc/polyline-materials

Make Polyline and Path use materials