GUI, preferences: reworked size settings:

- added size settings for player's panel size (closes #12455, closes #12451, closes #5605);
- size settings can be edit by slider or by text edit;
- size settings for fonts has preview button with real text sample;
- improved some tabs and hints for better UX;
- improved GUI rendering performance;

Mage.Client/src/main/java/org/mage/plugins/theme/ThemePluginImpl.java

@@ -82,6 +82,7 @@ public class ThemePluginImpl implements ThemePlugin {
             if (ui.containsKey("gamePanel") && ui.containsKey("jLayeredPane")) {
                 ImagePanel bgPanel = new ImagePanel(backgroundImage, ImagePanelStyle.TILED);
 
+                // TODO: research - is all components used? And why it make transparent?
                 unsetOpaque(ui.get("jSplitPane1"));
                 unsetOpaque(ui.get("pnlBattlefield"));
                 unsetOpaque(ui.get("pnlHelperHandButtonsStackArea"));