add code to bump up the number of requests.

not directly called; just hack it in to generate && write out
requests as need be.
new kernel, untested.

also implement a `flush_elem' and write my flushes in terms of that.
seems to have no impact on the naive kernel's performance.
way to run 'nosync' algorithm, and small fixes.

apparently there can be up to 450(ish) threads... it changes
arbitrarily?!

anyway this still dies.  towards the end, *every* thread tries to
insert '1', and it looks like *no* thread succeeds.  so when there
are only 54 brick requests left, nobody inserts everything, and
progress is not made.  hrm.