remove CD_MASK_NORMAL from CD_MASK_DERIVEDMESH, bmesh merge included this but its not needed.

Now add asserts to make sure this layer is only added once the modifier stack has been calculated.
this saves normal layer being calculated whenver vertex normals need updating.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@57146 954f8c5b-7b00-dc11-b283-0030488c597c
fix for incorrect use of strncat in uiItemMenuEnumO


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@57147 954f8c5b-7b00-dc11-b283-0030488c597c