number.toString(base) sometimes ignores argument

First off, while toFixed is now implemented, you can't cast to a number using Number(...) yet I'm afraid.

And no... Number(a.toFixed(0)).toString(16) is actually slower than parseInt(a).toString(16) on Espruino, because it'd involve the extra step of creating a number object.

To be honest if you wanted to be faster, you'd do (a|0).toString(16)

But it's a bit pointless now, because I just fixed the original bug. It'll be in 1v51 :)