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

fixed raw_changeset for git, accidentally it was generated with hg patch headers
- Code garden

Small fixes for style.
Added scm type for changeset.
Fixed raw changeset