RandomIdGenerator has weak PRNG seeding

[serac]

RandomIdGenerator uses weak PRNG seeding that makes it susceptible to producing duplicate identifiers under some usage patterns. For example, two threads creating new instances at exactly the same instant; both instances will produce exactly the same sequence of identifiers since the DRBG underneath is initialized with the same seed. That behavior arguably violates the principle of least surprise and could easily be corrected through the use of a seed with greater entropy.

[serac]

Pull request with fix: #41