New api proposal.
Added TOX prefix to enum.
Merge branch 'master' into new-api
New API done and tested.

Some stuff needs to be cleaned a bit though.
Forgot to commit a file in last commit.
Added tox_ to 2 typedefs.
Fixed some comments.
Replaced some defines with enums.
Merge branch 'new-api'

New, cleaner public API added. see: core/tox.h

This does not break anything because the old API is still there.

You are however encouraged to switch to the new API.