Browser support

[LarsDol]

Hi! Nice little plugin you've got here!

I've been using it in a project, though when I started testing different legacy browsers (IE9-11) I came across some errors. It might be nice to add some support for these, or list the intended browser support in the readme.

Some issues I came across:

• el.classlist needs a polyfill for IE versions (https://github.com/yola/classlist-polyfill).
• The RegExp objects used aren't recognized in IE ('Syntax error in regular expression'). Haven't had the time to check this one in detail, but I suspect the first parameter of RegExp should be a string, not an actual expression (https://stackoverflow.com/questions/16721057/ie8-is-not-recognizing-my-regular-expression]).

I might be able to fix these in a pull request later on, but for now it's just an FYI :)

Thanks!

[seiyable]

Hi LarsDol! Thanks for reporting the issue. I'll look into it as soon as I get a chance!

[seiyable]

Realized I don't have testing environment for IE browsers. I'd appreciate if you can fix and test it!

[LarsDol]

#8 - I've turned the regex into a string. Might get to the classList issue later.