This fixes three issues I ran into when running tests against the legacy ClearCase

implementation. Specifically:

When running on Python 3, there were some unicode-vs-bytes bugs in the diff parsing.
If the diff had incorrectly formatted filenames (which didn't include the vobtag),

  the diff parsing stage could infinite loop. I've added a fallback to ensure we don't

  loop more than a limited number of times.
The path normalization for display was calling realpath on a relative path, which

  (on Linux) would end up adding the CWD to the path. I've changed it so we first turn it

  into an absolute path relative to the repo root, run realpath, and then make it

  relative again.

Posted some changes using a dynamic view as the backend. Saw that I could post changes

without any errors, and that paths for files were displayed correctly.