shader primitives
sdf intersection
Merge branch 'daniel' of https://github.com/memo/VolumeRunner into memo

Conflicts:
	VolumeRunnerApp/bin/data/shaders/raytrace_test.frag
double rot speed
added render manager for fbo
Merge branch 'memo' of https://github.com/memo/VolumeRunner into daniel

Conflicts:
	VolumeRunnerApp/VolumeRunnerApp.xcodeproj/project.pbxproj
	VolumeRunnerApp/src/Camera.h