Screenshot Viewer Updates

Hi SG,

I was working on a few software updates to our web servers today and I had a bit of free time, so I updated the screenshot viewer with some requested improvements.

1. You can use the left and right buttons on your keyboard to move between images.
2. There are now arrow icons on the left and right side of images that can be clicked to move forward and back.
3. The Esc key will close the viewer.
4. You can click with your middle mouse button or use touch controls to scroll through the bottom thumbnails.

I'm going to be working on updates to our database next week, so expect a little downtime. The site will be offline for a few minutes when I snapshot the database for testing and then later in the week it will be down for an hour when I take the database server offline for updates. I'll post an announcement before and after the maintenance takes place.