Added JavaScript version for BigInteger and modify the Java version

[zhongliwu]

[divinity76]

first off, there's a merge conflict, could you fix that? 2nd, i think it would be better if the JavaScript and Java patches were in 2 separate pull requests

[ocram]

@divinity76 This pull request is old, so the author doesn't have any interest in this anymore, perhaps. But I agree with everything you said. In addition to that, I won't merge the JavaScript changes, anyway, since it introduces a new dependency which is never available in the browser out of the box. The Java solution with BigInteger can definitely be considered here.