BLI_math rename functions:
- mult_m4_m4m4 -> mul_m4_m4m4
- mult_m3_m3m4 -> mul_m3_m3m4

these temporary names were used to avoid problems when argument order was switched.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@57039 954f8c5b-7b00-dc11-b283-0030488c597c