Make use of APR for secure randomness cross platform

[dirkx]

Make use of APR for secure randomness cross platform, force the length of the nonce to be 144 bits; even if the struct is larger. Should fix #8

[wyattoday]

We're not going to use APR for RNG. It's very poorly documented.

Instead we use well documented PRNG for every platform (already in the code and tested on all major platforms).

[dirkx]

You are aware that it is not cryptographically secure - and without a per server context seed quite observable ? And I would image that this matters in this case ?

[wyattoday]

On Windows: it's cryptographically secure (see docs).

On macOS: it's cryptographically secure (see docs).

On Linux with a modern kernel: it's cryptographically secure (see docs).

Other unix variants: it depends on implementation details, but they tend to follow Linux's lead and be cryptographically secure.