delete old dead code
get rid of redundant _displayViewFrustum and use _viewFrustum
reset view frustum
implement support for entity subclasses to implement their own detailed ray intersection, make likes light pickability toggle
Merge branch 'master' of https://github.com/highfidelity/hifi into rayPickWork
support toggle of light picking in newEditEntities.js
Merge branch 'master' of https://github.com/highfidelity/hifi into rayPickWork
Merge branch 'master' of https://github.com/highfidelity/hifi into rayPickWork

Conflicts:
	examples/newEditEntities.js
	interface/src/avatar/MyAvatar.cpp
	interface/src/avatar/MyAvatar.h
	libraries/entities/src/EntityTree.h
Merge branch 'master' of https://github.com/highfidelity/hifi into rayPickWork
make sphere entities pick off their actual sphere, fix bug in ray picking multiple items with different distances
make text entities correctly ray pick
Merge pull request #3897 from ZappoMan/rayPickWork

Work on improving pickable entities - Lights Optionally pickable, Spheres & Text pick properly, other bug fixes