empty URL arguments are ignored
previous commit was too aggressive, was eating the pagination variable
Merge pull request #42 from rosskarchner/no_empty_q

empty URL arguments are ignored
API will 404 when query does not exist
Merge branch 'api_404' of github.com:dpford/sheer into dpford-api_404
Merge branch 'dpford-api_404'
Merge branch 'master' into error_pages
fix build_search_path and it's tests

Because of recent changes, a call to build_search_path without
either an 'append' argument or include_start_directory set to True
will return an empty list.

I no longer recall why "include_start_directory" is called that. Let's
think of a better name.
removed a PDB