Python Bindings and Backends

[John Ralls]

I noticed, while working on the python bindings, that it pulls in and attempts to init the xml and dbi backends. That's wrong for several reasons which I've documented in https://bugzilla.gnome.org/show_bug.cgi?id=634712.

I've written a patch to remove the gnc_module_backend_init_foo() calls from gnucash_core.i and the associated stuff from the Makefile. It works with simple_test.py in example_scripts, but I'd like at least one of the regular python users to test-drive it before I commit it.

Regards,
John Ralls