Tokstyle no longer allows:
* Includes inside an `extern "C"`
* Comments on function definition and declaration to be different.
* Doxygen comments commenting on other doxygen comments.
* make static functions return bool rather than int to indicate success
* add peer_in_list() to factor out uniformity over peer and frozen lists
* reduce repetition in send_lossy_all_close
* rename 'close' to 'connections'
* use uint32_t for peernumber (in accord with tox.c)
* explain persistence in tox_conference_get_chatlist documentation
* clarify "connectedness" in group API documentation
* clarify that tox_conference_peer_count counts only online peers
* refactor variously
* Fix `toxav_get_tox` to return tox, not messenger.
* Fix the casts from Tox* to Messenger* in toxav_old.c.
* Pass Tox instead of Messenger to public group AV callbacks.
* No anonymous structs.
* No assignment expressions.
* Only one declarator per struct member declaration.
* Named callback types only, no inline types.
* No `;` empty statements.
* `++i` instead of `i++`.
Avoiding a cast in toxav_old.c avoids some potential (and real) bugs.
"All rights reserved" was incorrect. The project was licensed under GPL3,
which means a lot of rights are licensed to everybody in the world, i.e.
not reserved to the "Tox Project".