update version to 2.4.0

- Bugfix - add member column `member_last_login` to setup sql
- Feature - add constant for trade filter to turn it off if you like
- Feature - delete all system messages
- Feature - refactor trade system
  - changed accept/decline system
  - added textarea for answering trades
  - adjusted trade layout
  - use trade filter on trade inbox page

Author: Shirisu

README.md

@@ -5,7 +5,7 @@ It's written in PHP and uses jQuery and plain CSS.
 
 It's based on the concept and script of "Tasty TCG" from 2016 but it's almost completely reworked.
 
-Current version: 2.3.0
+Current version: 2.4.0
 
 [Documentation - how to use autoPetiteTCGScript](https://github.com/Shirisu/autoPetiteTCGScript/blob/master/DOCUMENTATION.md)