Ydiff

- Dropped context diff support
- Handle East Asian wide characters (thanks to roy2220)
- Fix SIGPIPE issue on Windows (unofficial support, thanks to kingsamchen)
- Bump Python requirement to >=2.6 (Python 2 support is no longer tested)

- Support perforce workspaces
- Support pager customization via --pager and --pager_options
- Support running on Windows (requires ``less`` which is offered by git-bash)
- Fix a bug where reading stdin does not work outside a CVS workspace
- Fix tab expansion, expands to the next stop modulo tab width
- Performance improvement

- Rename from ``cdiff`` to ``ydiff`` to avoid binary name conflict on major
distributions, ``CDIFF_OPTIONS`` still works but will be deprepated soon
- New option ``--wrap`` to wrap long lines in side-by-side view

- Use environment variable ``CDIFF_OPTIONS`` to hold default options

- More robust parser to tolerate evil unified diff

- Fix unexpected side-by-side output for diff of diff
- Better color to work with solarized color scheme