Allow usernames to include ".", "-" and "_"
Summary:
See T1303, which presents a reasonable case for inclusion of these characters in valid usernames.
Also, unify username validity handling.
Test Plan: Created a new user with a valid name. Tried to create a new user with an invalid name. Ran unit tests.
Reviewers: btrahan, vrana
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T1303
Differential Revision: https://secure.phabricator.com/D2651