remove yield_metrics (was for old inspect)
make sure wtt tag has the proper values
add missing tags
deprecate the concept of multiple targets per metric.

* every available metric should represent one existing metric,
  and the metric should contain the appropriate information so that
  the code can "know" if there are more options (gauge -> rate, etc)
  without having to specify those explicitly on a per target level
* where we used the multi-target option to create different views
  and angles (moving averages etc), that's now deprecated.  it
  seems more appropriate that you specify "avg over x min" etc
  at runtime in your query (or even interactively with a slider),
  and/or choose a sane default based on the variability of the
  metric, and maybe, just maybe (probably not) rule definitions
  in your preferences that make GE apply certain mutations based
  on metric tags/metric_id
use mysql as storage of structured metrics

 * for compatibility with carbon_tagger, so that GE can use
   both metrics from carbon_tagger as well as structure_metrics
 * [so that you can speed up creation of structured_metrics, i.e.
   you can have multiple processes in parrallel working on a
   different slice of the partition space]
 * comes with a bunch of different implementations of querying,
   all of which are far from ideal, however. :(
use 'unit' tags in favor of old 'what' tags
rawes/requests submodules to support elasticsearch
query targets in elasticsearch. seems much better then mysql
add "timestamp" target_type
add todo
remove all mysql stuff. elasticsearch is clearly superior