If need to support normal diff, writing a ndiff to udiff translator
makes more sense

Without this, some of the logs will not be shown.

- Fixed a bug in diff format probe
- Handle keyboard interrupt and large diffs in non-color mode
- Code clean up

Previously, a keyboard interrupt would result in a corrupted terminal.
This would manifest when doing "cdiff --log" on somewhat large
repositories.

The user explicitly asked for a log and thus knows what he is doing.

This will use the patch log from git, svn, or hg.