Added some tests for ExtendedBitConverter.
Some methods moved from Int128/Int256 to ExtendedBitConverter.
Fixed bugs in DivMod() and added GetPrimeMultipliers() method to the MathUtils.
Updated license and readme.
Improvements of the ArrayUtils, ExtendedBitConverter, StringUtils.
Added BigInteger class from the Mono.
Renamed StringUtils.HexToBytes() method (old name was .ToBytes()).
Added few useful methods to the ArrayUtils.
Fixed bug with StringUtils.HexToBytes() which didn't support lower case hex chars. Also improved performance by adding lookup table.
Improvements of the ArrayUtils.
Changed version to 0.3.
Merge branch 'release/0.3'