Fixed issue that id of the status is rounding off

Since `enum JSON` was using double type for any numeric number, 
so that huge number (e.g. id of the tweet status) was rounded off when `enum JSON` created.

Example: 
I called getShowStatusesWithID() with id=508912145283575809, 
then the `JSON` of the response describes about https://twitter.com/gecko655/status/508912145283575809,
but id of the `JSON` was changed to 508912145283575808.

In my code, numeric number is treated as `Int` if `number.isEqualToNumber(number.integerValue)` is true.