Uncomment todos in output

[jml]

The old version used to uncomment TODOs. That is, it would take a comment like this:

    # XXX: Fix this thing
    # before it devours my soul.

and render it like this:

foo.py:21:
  XXX: Fix this thing
  before it devours my soul

Now that we support many more languages than just Python, this is kind of tricky, but still nice to have.