minimal/do: support searching parent dirs for .do files.
minimal/do: support searching parent dirs for .do files.

Now all tests pass again with both redo and minimal/do.

apenwarr/redo,dinkelk/redo-python,dinkelk/redo-python,apenwarr/redo,pombredanne/redo,apenwarr/redo,rowhit/redo,pombredanne/redo,rowhit/redo,pombredanne/redo,rowhit/redo,apenwarr/redo,pombredanne/redo,dinkelk/redo-python,dinkelk/redo-python,rowhit/redo