Support exponentials

[franciscolourenco]

The letter e / E is a valid way to represent a javascript number.

parseFloat('4e3') === 4000  // true

(4000).toExponential() === '4e+3'  // true

[lockevn]

That's true, but no normal-people enter 4e3 as 4000 in an normal input

[franciscolourenco]

They might if they are copy pasting from some place which uses scientific notation. There are of course more useful uses of the exponential notation than the example, otherwise it would not exist.

[lockevn]

Though I don't believe it totally, please give me some test cases (as much as possible), I might come back to this issue later.