BigInteger.java (BigInteger(String, int)): New constructor.
* java/math/BigInteger.java(BigInteger(String, int)): New constructor.
(BigInteger(String)): New constructor.
(not): Rewritten using version from Kawa's BitOps class.
(valueOf): New private methods from Kawa's BitOps class.
(swappedOp): ditto.
(bitOp): ditto.
(setBitOp): ditto.
(and): Implemented.
(or): Implemented.
(xor): Implemented.
(andNot): Implemented.
(clearBit): Implemented.
(setBit): Implemented.
(bitCount): Implemented.
(toByteArray): Implemented.
From-SVN: r31926