Allow filtering for users with .-_ in the username

Make it possible to filter for users, which have a .-_ in the username.

src/applications/differential/application/PhabricatorApplicationDifferential.php

@@ -41,7 +41,7 @@ final class PhabricatorApplicationDifferential extends PhabricatorApplication {
       '/D(?P<id>\d+)' => 'DifferentialRevisionViewController',
       '/differential/' => array(
         '' => 'DifferentialRevisionListController',
-        'filter/(?P<filter>\w+)/(?:(?P<username>\w+)/)?' =>
+        'filter/(?P<filter>\w+)/(?:(?P<username>[\w\.-_]+)/)?' =>
           'DifferentialRevisionListController',
         'stats/(?P<filter>\w+)/' => 'DifferentialRevisionStatsController',
         'diff/' => array(