[PATCH] cpp11-migrate: Add a class to support include directives modifications (Windows bot fix)

[Guillaume Papin]

  I tried to use the `current_path()` as well.

  I got an assertion using the command line equivalent to `["-I", current_path()]` which is needed if I use angled includes (otherwise an error shows up and says if this kind of paths are wanted I should use quoted includes). I believe the assertion showed up because the search path is process before the callback that overrides the file is called.
  Maybe there is some ways to get around this error but using "./" seems an easier solution. It works on Linux and I like to think that it doesn't rely on some Unix specific stuff, so it should work on Windows too.

http://llvm-reviews.chandlerc.com/D1438