btree: fix build error for enabled counters
Makefile: fix build for stats_client
counters: fix cache alignment issues

this introduces a variant of aligned_padded_elem/percore which is not
pedantic- we only enable non-assertion checking for counters (which we
don't really care about, and I don't want to go annotate all of them in
the code base)
benchmarks: add a stats collection runner
runner: update the factor analysis

disabling snapshots should also disable the *use* of snapshots
in the benchmark-- before we were running incorrect read-only
transactions
results: add numbers from the modified factor analysis benchmark
Makefile updates.

* Rebuild when relevant options change. Some of this was already
  supported in different $(O) dirs; others not.
* Support building without MYSQL, say MYSQL=0.
Fix VERBOSE compilation.