- blend_m3_m3m3 and blend_m4_m4m4 now support matrices with negative scales.

- python/mathutils api matrix.lerp(other, factor)
- new function mat3_to_rot_size(), like mat4_to_loc_rot_size but with no location.

source/blender/python/generic/mathutils_matrix.h

@@ -38,10 +38,9 @@ extern PyTypeObject matrix_Type;
 
 typedef struct {
 	BASE_MATH_MEMBERS(contigPtr)
-
-	unsigned char rowSize;
-	unsigned int colSize;
 	float *matrix[MATRIX_MAX_DIM];		/* ptr to the contigPtr (accessor) */
+	unsigned short rowSize;
+	unsigned short colSize;
 } MatrixObject;
 
 /*struct data contains a pointer to the actual data that the