Can specify --debug multiple times

- 2 times to add messages from ALPM
- 3 times to include ALPM's level DEBUG & FUNCTION
Change how icons are loaded, allowing easy override

All 4 icons used are now loaded from the theme - "kalu", "kalu-paused",
"kalu-gray" & "kalu-gray-paused" - so that users can easily override any (and
all) of them, simply putting files correctly named in ~/.local/share/icons