cache non obvious

[kapilt]

the cache behavior with hammet is not clear or documented afaics (nothing in the readme). it always reports against the cumulative files, even if just executing one, and its also unclear what it considers cache markers. re non obvious, ie. is it fast, or is it just not running any tests, use of cache should be noted in log output to clarify.

[boxed]

All solid points!

Maybe it should output two blocks of output, one for cached and one for what it actually ran?