random streams

[Brian Goetz]

On the list of requested stream sources is 'stream of random numbers'.

Here's a one-line addition to Random:

     public IntStream ints() {
         return PrimitiveStreams.repeatedly(this::nextInt);
     }

Certainly the implementation is straightforward enough (modulo renaming 
of PrimitiveStreams and repeatedly, which are not yet nailed down.)

Any objections here?  Clearly we'd want to support streams of ints, 
longs, and doubles, so just calling it stream() is wrong; should they be 
called random.ints(), or random.intStream()?