add support for Menu.menuExists() and menu.menuItemExists()
add editModels to defaultScripts
changed Models/Delete and Voxels/Delete to both use same menu item name of 'Delete' so that either option will correctly delete either.
fix bug in Menu::removeAction() where we weren't removing the action key from the hash, memory leak, and other problems
make editVoxels.js and editModels.js play nice together with the delete menu item
silence some unused variable warnings and move some debug code to only execute in debug mode
Merge pull request #2967 from ZappoMan/editModelsInDefaultScripts

Added Edit Models to default scripts
Merge pull request #2971 from ZappoMan/editModelsInDefaultScripts

Edit models in default scripts
Merge pull request #2969 from ZappoMan/silencewarnings

silence some unused variable warnings and move some debug code to only execute in debug mode