Probably fixes scrollTop issues with Firefox

Closes #1.
Closes #4.
Swap $scrollTop variable to $scrollBottom in $scrollBottom block of code
Add meta viewport in visual test
Remove throttle function and add necessity check
Add translateZ(0) to scroll operation to use GPU
Remove unnecessary variable, make factor calculation faster
Use Math.floor instead of parseInt for better calculation
Use native style property of event instead of jQuery's css-fn
Update README with better statement about where to put scripts
v0.2.0
Merge branch 'master' into gh-pages