diff parser: redefined operations stats for changes

- don't loose info about multiple operations like rename + chmod
- new Binary flag when dealing with binary file operations
- fixed diffs after mercurial 2.6 when GIT binary diffs were fixed
- added more tests for multiple operations

- refactored the way diffprocessor returns data. It's
now easier to extract type of operation on binary files
- diffprocessor doesn't append that information into the diff itself

Implemented generation of changesets based
on whole diff instead of per file diff. That
can give a big speed improvement for large changesets in
repositories with large history.
- improved handling of binary files
- show renames of binary files
- implemented new diff limit functionality
- unify diff generation between hg and git
- Added binary indicators for changed files,
- added diff lib tests