XOR in random value to scalar and perform special scalar multiplication.
Multiply x3 and z3 by random value to randomize co-ordinates.
Add new APIs to support passing in an RNG.
Old APIs create a new RNG.
Only needed for the C implementations that are not small.
Modified TLS and OpenSSL compat API implementations to pass in RNG.
Fixed tests and benchmark program to pass in RNG.
bb84ebfd7a