Add 1080p ultrawide support and fix script bug

Created by: jgabriel98

adds 1080p ultrawide (2560x1080) support. Also fix a bug in the install script: when install.sh is launched as non root, after requesting the password, it losses every argument except for theme name and resolution related. For example, it will lose the --white flag, and install color icons instead.

for some reason jpeg didn't work for ultrawide so i had to switch to png (only on ultrawide). Maybe i can blame the way my image files where generated?