moved some math routines to separate directory

c64/basic/math_mov/bba2.interop

@@ -0,0 +1,4 @@
+This is an important floating point math routine, documented in many places.
+
+Routine probably used very often, it's call can be seen in a tutorial here:
+- https://codebase64.org/doku.php?id=base:generating_sines_with_basic