…finition order.

Author: wsanchez
Reviewer: exarkun, hawkowl
Fixes: twisted#6523

The order in which constants are defined is now also the comparison order for constants.  This is now explicitly implemented with tests and the documentation has been updated.


git-svn-id: svn://svn.twistedmatrix.com/svn/Twisted/trunk@41925 bbbe8e31-12d6-0310-92fd-ac37d47ddeeb