allow searching for issues with empty topics [SF#610787] points out that the classic template doesn't allow a way to search for issues that don't have a topic. Priority, status, and assigned do, so I've remedied the oversight by adding a new option to Topic. This closes [SF#610787].

#!/usr/bin/env python
import zlib, base64, sys
print base64.encodestring(zlib.compress(sys.stdin.read()))