Number methods, plus [].remove(member)

Hi Mike,

Just thought I'd see if you were interested in these methods I'd been using. `array.remove(member)` is something I need constantly, I don't really understand why it's not already part of the language. The number methods are just from `Math` - I like being able to do `num.round()` instead of `Math.round(num)`.

Have added tests but not docs, if you merge this (or part of it) I'll send a separate PR to gh-pages.

Cheers,

Rich