Some notes for maintainers

Please don't use Python 2.x specific code as long as PyGTK doesn't
require Python 2.x!

Always make sure that optional features are enabled by default.  For
example, use "#ifndef WITHOUT_NUMPY" instead of "#ifdef WITH_NUMPY"!

If a GtkExtra function is changed or added the following files have to
be edited:

* __init__.py
* gtkextra.defs
* gtkextra-extrafuncs.defs

For PyGTK 0.6.x:

* gtkextramodule.c

  Generate "gtkextramodule_defs.h" and "gtkextramodule_impl.h" with
  "python ../codegen/mkgtkextra.py".

For PyGTK2:

* gtkextra.override

If a GtkExtra type is changed or added the following files have to be
edited:

* <type name>-type.c
* pygtkextra-private.h
* pygtkextra.h

Some types require additional code that is placed in:

* <type name>-support.c

Common code is placed in:

* gtkextra-support.c
