fix for #5 - allow multiple characters

[wwalker]

This is a patch (revert really) to fix #5 "Can no longer use multiple keys for a hotkey".

It also brings back the automatic lower casing of the hot keys.

[DaveDavenport]

The lowercasing was removed so it follows rofi's setting. To keep things consistent (and on user request).

[wwalker]

Thank you. I totally understand (now, I misunderstood what it was being compatible with (blezz vs rofi)).

Thank you for rofi, and for rofi-blezz!