Make user name mapping optional.  Refs #8961.
Make user name mapping optional.  Refs #8961.

Setting `userMap=0` disables mapping of user IDs to full names.
(Defaults on.)

Thanks to bof for the patch.

git-svn-id: 2159781fc7c14c6bdd1f7e265daf7a25099c31e7@10410 7322e99d-02ea-0310-aa39-e9a107903beb

trac-hacks/trac-jsGantt,trac-hacks/trac-jsGantt,trac-hacks/trac-jsGantt