Fixed screenshots.

Debian package link added.

Also fix a typo.

I created a package for slop currently in the 'fkmclane' overlay that can be added through layman (`# layman -a fkmclane`).

Not sure whether to link to http://repo.voidlinux.eu/current/ or the template that I constructed, which was processed by the buildbot after the merge.

Cleaned up code
Windows are now selected via EnterNotify events
Improved response time on rectangle drawing (no longer creates new rectangles when window selection changes, waits 0.01 seconds between re-drawing for xorg to catch up and display)
Removed offset settings as they seem useless
Added --version option
--nodecorations now doesn't attempt to actively search for the correct subwindow. Now it just allows for selection of subwindows. This should keep slop from crashing/not work properly on weird WMs like openbox, but may make it act a little unexpectedly since you can still click on decorations to include them.