Add some update notifiers for a few boolean paint properties (probably a
lot more needed) so that they get properly updated in UI when the
property is edited through python or a custom key binding to context
toggle operator.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk@61006 954f8c5b-7b00-dc11-b283-0030488c597c