Update to catch up with toxcore.

[gbin]

just the minimal thing to make it compile against libtoxcore: type parameter in the group chat (text/audio stuff)

• added the 2 group_set/get_title missing.

[aitjcize]

Nice work! Thank you so much for contributing :) It would be even better if you can add a test case in tests/tests.py :P

[gbin]

@aitjcize Sure I gonna have a look at it.