Ubuntu Tweak 0.8.4 Released to Support Ubuntu 13.04

Beside the support for Ubuntu 13.04, Ubuntu Tweak 0.8.4 also fixes a few annoying bugs, such an unexpected issue that appears when installing apps through Ubuntu Tweak, correctly upgrade the path of scripts on Ubuntu 13.04. Ubuntu Tweak 0.8.4 also fixes rare crashes that appear while updating the software list, the Janitor only shows ???System??? issue, and the window button tweak error in Ubuntu 13.04.