Added firefox & IE support + fixed callback not firing.

[gijsroge]

• This will add support for Firefox and Internet Explorer.
• Add a check if scroll reached bottom page to trigger callback

[gijsroge]

Note: removed the hardcoded fix for scrolling with the body element. You should include this polyfill to fix the issue -> https://github.com/mathiasbynens/document.scrollingElement

[derek-schultz]

Why was this never merged? Does it still work?

[gijsroge]

@derek-schultz Probably because they are busy which is perfectly reasonable, in the mean time you can use my fork. https://github.com/gijsroge/animated-scrollto

[nikoloza]

@gijsroge I used your repository as replacing NPM package of this one, but it still does not work on FF

[gijsroge]

@nikoloza Did you add the scollingElement polyfill? See: https://github.com/gijsroge/animated-scrollto#browser-support