code cleanup: use boolean for intersection functions.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@57323 954f8c5b-7b00-dc11-b283-0030488c597c
fix [#35663] Some object types don't draw bounds other than "Box"


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@57324 954f8c5b-7b00-dc11-b283-0030488c597c