New feature request: `--exclude-directory=PATTERN' and `--include-directory=PATTERN'

[Clark J. Wang]

Current grep supports two great options `--include=PATTERN' and
`--exclude=PATTERN'. But when I grep something from within a chcked out
subversion directory I want to skip those directories named `.svn'. So it's
better to let grep support `--exclude-directory=PATTERN'  and
`--include-directory=PATTERN' options.

Thanks.