convert string cleanup

[Andrew Bartlett]

Jeremy,

What are your plans for cleaning up the convert_string API that you
mentioned in your recent commit?

I'm just keen to ensure we don't step on each other's toes.  

For my part, I'm planning to add the requested tests for the two
convert_string implementations, using the handles in the samba4 side to
loop over multiple combinations of unix and dos charset, and deliberatly
using combinations of greek and ascii text to confirm both the fast and
slow paths. 

Andrew Bartlett
-- 
Andrew Bartlett                                http://samba.org/~abartlet/
Authentication Developer, Samba Team           http://samba.org
Samba Developer, Cisco Inc.