Issue Summary

By issuing a user search with multiple spaces it is possible to put high load on the database server.

Steps to Reproduce

1. In the user picker type '  a' (two spaces followed by an a, or indeed three spaces)

Expected Results

No requests made to server as the request should only be fired when three or more characters are typed.

Actual Results

The request is made to the server, it trims the spaces and issues a very inefficient query that may load the entire userbase into memory over a long period of time.

Workaround

Don't issue user searches with multiple leading spaces