#4 tko file extensions

[Auriel Manolson]

As your appliction uses it's own format, it would be
nice to have a file extension for this:

I would suggest: tko

which is not taken according to all of the lists below

http://filext.com
http://www.stack.com/file/extension/
http://whatis.techtarget.com/fileFormatT

I have alreayd configured my windows system to
associate .tko files with tkoutliner