Start refactoring query_invindex & rename it to invindex_query
Start refactoring query_invindex & rename it to invindex_query

....but of course it's not finished yet. We're doing well, but there are 
a few thorny issues to go.

Mainly: We need to seriously optimise ids::getpagename(), 'cause we'll 
need it a *lot* when we get to implementing the size, before, and after 
colon : directives.

sbrl/Pepperminty-Wiki,sbrl/Pepperminty-Wiki