Simplified the info tests.

- Use a table to validate what we care rather than trying to smoosh
  results into the answers.
Implement pathinfo dual fallback

- Now address both files and directories.
Git repo creation.
Rebuild the subrepo in repodata correctly.

- Need to put them in the ext subtree to ensure consistency with what
  was in pmr2.mercurial.
Wrote a way to parse a .gitmodules string.

- Someone else can bring in the proper bindings into pygit2 from libgit2
  for accessing submodules information.
Git submodule support.

- Implemented in a way similiar to how pmr2.mercurial is done, or rather
  what the current front-end renders expect.