Blender Git Loki

new draw path for Mesh & Camera objects

Used only when �??new viewport�? pref is checked, so we can switch back &
forth for comparison.

Camera because it�??s simple �?? scoped some vars, removed an extra line
segment, touch back face cull state only when needed.

Mesh because it�??s interesting �?? very little difference, just factored
out edit mesh drawing & touch back face cull state only when needed.

Also added (temporary) call graph tracing, to help me make sense of the
object drawing logic.

More to come for these object types, will run with these and add more
object types later. Not using our new APIs yet but that is the goal.