[Experimental] Themes system is works!
you can:
- customize toolbar and window icons
- customize some cursors
- customize player points images
- customize default splash

Issue: state of current theme pack saving is not correctly when you try to set "Default" theme when in current config pack is defined other theme pack.
When you check "Default", will be re-Selected to theme pack which defined in the config as "default-theme" of main.ini [gui] section.