a little spring cleaning to remove some compiler warnings for

implicit declarations, redundant redeclarations, missing initializers,
nested externs and other cruft.

Cleaned up includes and moved extern _Type decls from Types.h into
Types.c since that is the only place where they are needed now.

Did not touch Ipo.[ch] since work is on-going there.

source/blender/python/api2_2x/Mathutils.h

@@ -40,7 +40,6 @@
 #include "quat.h"
 #include "euler.h"
 #include "point.h"
-#include "Types.h"
 
 PyObject *Mathutils_Init( void );
 PyObject *row_vector_multiplication(VectorObject* vec, MatrixObject * mat);