Changes for version 0.05
- zero the buffer as soon as the bytes it's holding are no longer needed (in accordance with MSDN documentation). Zeroing does not happen if both SecureZeroMemory() and ZeroMemory() are unavailable.
- Prototype the subroutines listed in 'use subs()'.
- Do "unpack 'J'" and "unpack 'L'" instead of "scalar reverse unpack ...". (Otherwise we can get leading zeroes in the output.)
XS wrappers of CryptGenRandom and RtlGenRandom.