[Bf-python] Documenting existing problem with current API

[Ken Hughes]

Ok, so obviously I'm bored today and am trying to find something to do, 
so decided to look back thru my bf-python ML backlog.  Discovered what 
seem to be a lot of unresolved issues which we haven't fixed yet, either 
waiting for the big API refactor or things which have slipped into the 
cracks (and maybe some things which have been fixed and I just forgot).

Things like:
* Euler radian vs degree issue (which we've discussed recently)
* Mathutil methods which modify their data AND return a copy 
(vec.invert() for example).
* Object.New() and flaky user counts

And probably others I've forgotten.

Does it make sense to put these on the wiki somewhere as issues to be 
resolved, just so we have them documented somewhere?  And also whether 
they're on a to-do list or a refactor waiting list?

Ken