remove hash selection in New.
Update package READMEs.
Fortuna clean up, improve robustness, add AutoUpdate.

* AutoUpdate: update seed file every 10 minutes and on shutdown,
* public functions ensure the PRNG has been initialised before
  proceeeding,
* hash function is no longer use-selectable,
* reading a seed file increments the counter, making the PRNG ready for
  generating random data immediately; while not explicitly stated in the
  algorithm, this appears to be the designers' intent, and
* formatting.
tunafish given same improvements as fortuna in last commit