Removed the drawSelectedVerts and added drawSelectedVertices, which uses dm->foreachMappedVert.
In calc_weightpaint_vert_color():
Made the weight paint color black and return instead of input=-1
Made the pose bone selection normal when multi-paint is inactive.
Name fix for functions using mv instead of mvert.
Used vector functions provided by the math lib.
Changed some MEM_callocN references to be stacks.
Changed dm_deform_clear to use ob->derivedDeform primarily
Made the variable "float **changes" into "float (*changes)[2]"
Used CTX_data_active_object() in place of CTX_data_pointer_get_type()
Added the invert selection hotkey "Ctrl+I" to weight paint's vertex mask.