Add awaitAll and awaitAny that work with ForkIO

[louthy]

The existing IO.awaitAll and IO.awaitAny all work with either IO<ForkIO<A>> or K<M, ForkIO<A>>. So, this works:

IO<A> op = ...;
var fa = op.Fork();
var fb = op.Fork();
var fc = op.Fork();
var result = IO.awaitAll(fa, fb, fc);

But, this doesn't:

var result = from fa in op.Fork()
             from fb in op.Fork()
             from fc in op.Fork()
             from _  in awaitAll(fa, fb, fc)
             select unit;

So, we need awaitAll and awaitAny that take raw ForkIO values, not just IO<ForkIO<A>> values.

awaitAll workaround

Use the .Await property of the ForkIO an then monad-chain the forks:

var result = from fa in op.Fork()
             from fb in op.Fork()
             from fc in op.Fork()
             from _  in fa.Await >> fb.Await >> fc.Await
             select unit;

That will wait for fa, fb, and fc to complete before continuing.