fancyopts: add early-options parser compatible with getopt() The next patch will add a flag for strict parsing of early options, where we'll have to parse all early options at once instead of processing them one-by-one by dispatch._earlygetopt(). That's why I decided to hook fancyopts(). All dispatch._early*opt() functions is planned to be replaced with this function. But in this stable series, only the strict mode will be handled by fancyopts.earlygetopt().

To run the tests, do:

cd tests/
python run-tests.py

See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.