Add version number and some functions/macros to operate on it.
Fix LAN discovery tests.
Test ipv6 bootstrap.
Split load/save empty-file test.
Move class ToxCore C++ native code to ToxCore directory.
Also check for length of saved byte arrays.
Merge load() and new().
Add another failing C testcase
Move testcases out into separate functions.
Avatars still need names.
Add tox/av.h and implementation stubs.