Scroll counter

When NohBoard didn't support the scroll wheel yet, I added the scroll wheel support functionality for my friends to use and they liked it. It was showing the scroll counter resetting every second. Now that NohBoard has updated to detect various scroll directions, I decided to update my scroll counter thing as well. I also decided to Pull Request it here because other people might like it. The scroll counter is toggled with **scrollCounter** seting in the configutation file (defaults to 0), best used with **scrollHold** set to 1000.

I also added a keyboard file (*us_intl_fpsgame2.kb*) that has scroll wheel buttons in addition to others.