* pagespec_match_list: New API function, matches pages in a list
and throws an error if the pagespec is bad.
* inline, brokenlinks, calendar, linkmap, map, orphans, pagecount,
pagestate, postsparkline: Display a handy error message if the pagespec
is erronious.
for extended pagespecs. The old calling convention will still work for
back-compat for now.
* The calling convention for functions in the IkiWiki::PageSpec namespace
has changed so they are passed named parameters.
* Plugin interface version increased to 2.00 since I don't anticipate any
more interface changes before 2.0.