Changing user profiles
Voice Chat
Video Chat


Bugs:
Check which pointers are freed by the lib and which must be freed by the
client, and document these.

Make function arguments and return values const correct (check if all targets
can handle it)

Use enums instead of int where appropriate (yahoo_status, for example)

Make sure that ALL callbacks which could refer to multiple profiles include
the profile as an argument

Move error handling to the appropriate place (ext_yahoo_error instead of
ext_yahoo_login_response)