Use ordinary DRAWABLE_GEOMETRY flag on 2D drawables so that they can be raycasted against. Use a DRAWABLE_PROXYGEOMETRY flag on DrawableProxy2D so that it won't show up in normal raycasts or octree queries. Fixes #345.
Travis CI: API documentation update at 2014-05-14 12:16:59 UTC.
[ci package]
For Travis CI - switch CI build to use OS X build environment.