gnome-screenshot-import: bring back
gnome-screenshot-import: rename to cap.pl
cap.pl: allow case-sensitive opts

Otherwise -F does not work. Derp.
cap.pl: fix some syntax errors
cap.pl: give a better name to $obj
cap.pl: show an OSD for area screenshots
cap.pl: show a notification about screenshot failure
cap.pl: upload screenshots to imgur
cap.pl: remove --file option
cap.pl: use counter instead of H:M:S in names
Revert "cap.pl: use counter instead of H:M:S in names"

This reverts commit aa27d9edc3924f8961da5284fd4b8ecc503c8187.

Race condition and ugly code is not worth it, even if I think cap.sh's
names looked nicer. (Besides, if I delete an older screenshot from
today, a hole is created.)
cap.pl: rename to cap
cap: re-add the -N option
cap: use screenshot as the notification icon