Unified logging and meta-cubifying of internal progress

Cleaned up and standardized the `util.log` statements and the `meta` statements into a metalog module:

* `metalog.info('foo', {...})` for progress recording -- sent to log by default
* `metalog.minor('foo', {...})` for verbose recording -- sent nowhere by default
* `metalog.event('foo', {...})` cubifies the event and sends it to info
  - `metalog.event('foo', {...}, 'silent')` to cubify but not log
* retarget log statements by reassigning the appropriate `metalog.loggers`: for example, say `metalog.loggers.minor = metalog.log` to log minor events (be verbose), or `metalog.loggers.info  = metalog.silent` to quash logging.