Fix a couple of nondeterministic test failures
Some benchmarks working
Enable another benchmark
Fix some more test ordering things
Use an updated 'a' package to make benchmark assertions nicer
Fix all bench_tests
Get insertion benchmark running

On my machine I can insert at ~130k rows/s, flushing every 50k rows,
onto a spinning disk. Should be plenty fast for now.
Hit slice grouping in the bench tests for apples-to-apples comparison
Fix a TODO
Less redundant HandlerFunc naming
Return dimension table row names as a plain array

Including the index is duplicate information the callers end up stripping out.
Add route to get a single dimension
Port a partial change over from master.

Taken from 443dfd2d0d5e6a61a1ead5e39effd33b1f4a1c5e.
Readability improvements to the interval/merging code

Based on code review by Daniel.
Split out runtime configuration from the schema

Also use reasonable defaults.
Remove unneeded runner package
Plumb errors through flush()
Don't automatically flush from gumshoe

Leave this to the caller (server). This is a much nicer separation of
concerns and makes some upcoming changes simpler.
Plumb flush errors through to Close() as well
More structure for schema and configuration options

- Split schema from gumshoe runtime configuration from server
  configuration
- Make DiskBacked a first-class notion