Domain 'all' in hook_faceted_search_collect() becomes 'facets' to distinguish from other types of filters.

Fixed search arguments sometimes being messed-up when parsed (depending on the order they were processed).

Simplified URLs. Made some nice generalizations that also simplify the code and slightly improve efficiency.

Made specialization easier through a simpler structure. Also ceased to assume that the generic implementation would work for all types of fields (it did not).