Sig-check timer

[Former user]

Would be nice to have a timer running in the sig list that shows last sig-check. So people can be aware, that a system hasn't been checked for a x-amount of time. Or has been sig-checked 2 minutes ago, so not wasting my time going in that certain pipe.

[Josh Glassmaker]

Added last modified time & character name to the hover over for signature list age column