Removed a TODO that is already addressed.

TODO.md

@@ -4,6 +4,5 @@ TODO
 * Turn the benchmarking script at pystache/tests/benchmark.py into a command in pystache/commands, or
   make it a subcommand of one of the existing commands (i.e. using a command argument).
 * Provide support for logging in at least one of the commands.
-* Make sure doctest text files can be converted for Python 3 when using tox.
 * Make sure command parsing to pystache-test doesn't break with Python 2.4 and earlier.
 * Combine pystache-test with the main command.