simplified frustum camera mode, fixed resizeGL in case of frustum being on
Merge branch 'master' of https://github.com/worklist/hifi

Conflicts:
	interface/src/Application.cpp
	interface/src/Camera.cpp
cleanup resizeGL, and Display Frustum menus
CR feedback
Merge pull request #823 from ZappoMan/master

Display Frustum and resizeGL() cleanup