Mathutils API: Euler support for rotation order.

Examples.
 euler = Euler(1, 2, 3)
 euler.order = 'ZXY'
 
 euler = matrix.to_euler('XZY')


Still missing rna support. this still wont give the right order, defaulting to XYZ.
 eul = object.rotation_euler

source/blender/python/generic/Mathutils.h

@@ -37,8 +37,6 @@
 #include "quat.h"
 #include "euler.h"
 
-/* #define USE_MATHUTILS_DEG - for backwards compat */
-
 /* Can cast different mathutils types to this, use for generic funcs */
 
 extern char BaseMathObject_Wrapped_doc[];