Add a mode parameter to help control output.

Added a mode parameter to the concept search. If this is set to
'dijitFilteringSelect', the behaviour changes slightly to conform better
to a dijit.form.FilteringSelect widget.
Remove logging.
Change route from .concept to .c

Currently routes contained concept(s). Since skosprovider now supports
both concepts and collections through these url's, this is no longer
accurate. Therefor, /concepts and /concepts/[concept_id] have been changed
to /c and /c/[c_id].

Also added a functional unit test for the /c/[c_id] route.
Removed deprecated FlatDictionaryProvider.

FlatDictionaryProvider has been deprecated in skosprovider 0.2.0, and
should be replaced with DictionaryProvider. Also removed unused import.