Fixed example to clarify that gaussian velocity initialization can lead to center of mass motion.
Fixed example to clarify that gaussian velocity initialization can lead to center of mass motion.

git-svn-id: d6ecbb21cdb041a347ee95bdc4b0daa5df687b0e@2440 fa922fa7-2fde-0310-acd8-f43f465a7996

joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue