remove some unecessary null pointer checks
added rectangular range limits
fix bug in editVoxels.js that wasn't deleting menus
fix potential crash in setIsOptionChecked() added support for positioning separators
Merge pull request #2167 from birarda/null-checks

remove some unnecessary null pointer checks
Merge branch 'master' of https://github.com/highfidelity/hifi
Merge pull request #2168 from PhilipRosedale/master

added rectangular range limits
Merge branch 'master' of https://github.com/highfidelity/hifi
Merge branch 'master' of https://github.com/worklist/hifi into bugfixes
Merge pull request #2169 from ZappoMan/bugfixes

Menu scripting bug fixes
fix a flipped null check
Merge pull request #2173 from birarda/null-checks

fix a flipped NULL pointer check
Merge branch 'master' of https://github.com/highfidelity/hifi
Fix for annoying "QThreadStorage" warning.