in-game hud: ball marker

Started framework for ball marker, currently it will mark a players ball, pulling information from network variables (checks to make sure nvs is in scene before attempting to work).

Commit is made using prefabs for easier merging.  To implement in scene, simply attach BallMarker.cs to one of the prefabs instantiated per player by the network manager (I was attaching it to Lil' Patrick prefab, for example) and make sure you assign the one prefab it asks for in the editor (use Ball Marker Prefab).

Note: because this relies on networking, it will probably only work in scene "Main" as of the current build.

Should look like this: http://imgur.com/bpPzySz