Index toplevel of loadpaths

[trans]

Maybe a "2.0" API change. The idea is to index the toplevel of each libraries loadpath rather then just the library itself. In other words there would be a third index file that listed, in the the case of facets:

facets/        /.../lib/core/
facets/        /.../lib/more/
facets/        /.../lib/stnd/
facets.rb      /.../lib/core/
facets-live.rb /.../lib/core/
facets-load.rb /.../lib/core/

This could then be used to quickly match require/load paths, reducing the number of locations that need to be searched even for a traditional full-loadpath fallback search (currently the slowest part of the system).

[trans]

Of course, we could also go so far as to index all files. But that is almost certainly overkill. And it would mean re-indexing whenever a file is added or removed from a project. Indexing just the toplevel only means re-indexing need only occur if something in the toplevel has changed. But usually that is not the case, because most projects use foo/, foo.rb standard.