Stricter number parsing in Float.fromString and Int.fromString

[glennsl]

Implements the changes proposed in #86. See the differences in the tests for specifics on behavioural changes.

Note also that this drops the radix option of Int.toString, but on the other hand improves parsing of radix prefixes in the string itself, i.e. 0x, 0o and 0b.

[jmagaram]

Got a big laugh reading this. Especially “worst of all the bad options”. And interesting to learn there is a Number object distinct from the primitive - glad to have that in my toolbox. A couple thoughts…

Group them together so the user will see a menu of related choices. So parseString not fromString. If you want to encourage use of your implementation call it parse.

In the doc help for each explain the limitations and behavior like “Unreliable behavior if the string includes separators or characters not part of the number.” Give a few bad examples. Point to MDN.