"About" link added

I have created an "About" link at the bottom of the side pane with the version info and link to website in the pop-up.

I created a new "aboutIITC" function and placed it in main.js - this may not be the best place for it, but I couldn't find a relevant section under /code/.

I'm not too familiar with Greasemonkey scripts or this project, so there is likely a better implementation of what I created.