Ticket/12286 Update Coding Guidelines


- [x] Classes use namespaces now
- [x] Most classes have been moved to phpbb/ instead of include/
- [x] styles.php does not exist anymore
- [x] Function names should be prefixed with phpbb_
- [x] request_var() should not be used but $request->variable()
- [x] style.cfg should not use html but uft8 (c)
- [x] Styles should have style and phpbb version in their .cfg
- [x] Template events are missing * Since line
- [x] utf8_normalize_nfc() around requested utf8 variables is not needed (done by the class)
- [x] Translation section should have a link to https://wiki.phpbb.com/Plural_Rules

http://tracker.phpbb.com/browse/PHPBB3-12286