Fixing ActivityLookup
Fixing ActivityLookup

ActivityLookup had two issues:

* If the user had no Project selected, then `''` was passed in as the term, causing the invalid function call `Project.objects.get(pk='')`.
* In any case, even if a Project was selected, nothing in Lookup's `get_query` method was returning a restricted set of results.

Two things are added:

* The default value for `request.GET['project']` is set to `None`, and a guard is added to ensure that the value is non-`None` and non-`''`.
* The successful return value is restricted by the search term.

caktus/django-timepiece,caktus/django-timepiece,caktus/django-timepiece