Review Request: BigInteger patch for efficient multiplication and division (#4837946)

[Tim Buktu]

Hi Brian,

thanks for the update.
> This patch differs from the code in https://github.com/tbuktu/bigint.git. Notably I observed that Schonhage-Strassen multiplication and Barrett division are not present. Is this intentional and if so why would that be? Are the implementations of these additional algorithms not quite ready for contribution or is there a licensing issue perhaps?
Schönhage-Strassen and Barrett have been tested by me. I believe Alan
Eliasen also ran tests. There are no known bugs and there shouldn't be
any licensing issues because I wrote the code myself.

The reason why I didn't include these two algorithms in the patch I
posted here is because I wasn't sure if it was too much code to review.
If that is not a problem and you'd rather use the full implementation,
the four patched files are at

https://raw.github.com/tbuktu/bigint/master/src/main/java/java/math/BigInteger.java
https://raw.github.com/tbuktu/bigint/master/src/main/java/java/math/MutableBigInteger.java
https://raw.github.com/tbuktu/bigint/master/src/main/java/java/math/BigDecimal.java
https://raw.github.com/tbuktu/bigint/master/src/test/java/BigIntegerTest.java

Let me know if there are any more questions.
Thanks,

Tim