- operator definitions, callbacks, registry to WM and handlers for it are
now always in a file xxxx_ops.c or xxxx_operators.c, in the bottom you
will find the registry and handler code.
- fixed some confusing naming conventions "rip_area vs area_join" etc. Now
stick to convention to first name subject, then operation (like UI :).
So it's area_rip, screen_add, and so on.
- Nicely put exported calls (outside module) together in bottom: this using
names such as ED_screen_duplicate().
- Moved Operator-Property API to new C file.