Progress on Bug #5

We're ripping up the whole code base, and moving everything to the async
idiom.  To prevent locking up the browser....
work ongoing on issue #5
this is a plausible interface....

but not sure if it's the right one or not....
going back on forth on this...

not sure if it's the right thing to cb with a null err if err will
always be null, or rather to leave it off.
for some horrible reason, setTimeout is going nuts...

During the delay slot in Salsa20.  I'm very confused by this, but I'll
work on it later, I'm starving now.
uggg, so flumoxed by this!
well everything works...

But performance might really be suffering

i should look more into it
some twiddling with performance
check in debug code for chris
ok, back out debug changes
Close #5 and merge this back in

We have lots of changes to make, but let's do it on the master branch.
Merge branch 'async'