Avoid test flags in normal binary.

Change-Id: If1fba813a73bf93ea5918dcda326e3ffa81a797d
Squash a few trivial TODOs.

- Delete unneeded file view_adapter.go.
- Assessed that we still need the fingerprints in nodes
  (to create iterators).
- Turned numMemChunkDescs into a metric.

Change-Id: I29be963c795a075ec00c095f76bf26405535609d
Completed more TODOs.

- Documented checkpoint file format.
- High-level description of series sanitation.
- Replace fp.LoadFromString panic with an error.
  (Change in client_golang already submitted.)
- Introduced checks for series file size where appropriate.
- Removed two Law of Demeter violations.

Change-Id: I555d97a2c8f4769820c2fc8bf5d6f4e160222abc
Fix typo.

Change-Id: I72608c7841c00145458807d3c3ee29db7b5ac2bc
Merge pull request #413 from prometheus/cleanup/do-some-todos

Cleanup/do some todos