Allow . in usernames

patches/server/Validate-usernames.patch

@@ -21,7 +21,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +        for (int i = 0, len = in.length(); i < len; ++i) {
 +            char c = in.charAt(i);
 +
-+            if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || (c == '_')) {
++            if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || (c == '_' || c == '.')) {
 +                continue;
 +            }
 +