dispatch: alias --repo to --repository while parsing early options
This prepares for replacing old _early*opt() functions. My initial attempt
was to extend options table to support 'repository|repo' syntax. It worked,
but seemed too invasive. So I decided to add an optional argument to
fancyopts() instead.
This also changes the nevernegate dict to be keyed by a canonical_name,
not by an option-name for clarity.