Update README.md and add ScrollTo 'top' & 'bottom' support

Hi,

This pull request is for two items as I'm unable to create topic branches using the website and I have no client available.

README.md update includes all the documentation pulled from your site which I have expanded on and added reference to the slimscrolling event. Hopefully this will help new users pick up your library easier..

Commits relating to this:
586a871
a624eca
a821116

Second part: 

ScrollTo support for 'top' and 'bottom'. I needed support for 'bottom' personally, and 'top' was the fallout to keep it consistent. You will see commit 87647fd adds this in to the README.md, so if you're not bringing in the second part, do not merge this in.

Examples also updated relating to ScrollTo

Minification done with jscompress.com