Adding collisions options to menu at a second location.

And adding CollideWithParticle option which will be working soon...
Cleaning up collision check API's and re-enabling collisions with particles.
Merge branch 'master' of ssh://github.com/highfidelity/hifi into avatar-interaction
Helper method for adding avatar collision submenu
Merge branch 'master' of ssh://github.com/highfidelity/hifi into avatar-interaction
Remove warning about null-op sprintf() in g++
Merge pull request #2003 from AndrewMeadows/avatar-interaction

Particle vs Avatar collisions work again