GUI, game: improved battlefield sizing (part of #6887 and #969):

- fixed wrong restore of card hint and chat panels;
- now it keep hidden state too (e.g. hidden card hint);
- reworked and share splitters code;
- removed some useless hotkeys to show/hide card hint panel;

Mage.Client/src/main/java/mage/client/table/TablesPane.java

@@ -115,6 +115,7 @@ public class TablesPane extends MagePane {
 
     @Override
     public void deactivated() {
+        super.deactivated();
         tablesPanel.stopTasks();
     }