Add script for evaluating service accuracy via measurement feedback, close #31.
Merge pull request #216 from graydon/bug-31-simulate-queries-from-measurements

Add script for evaluating service accuracy via measurement feedback
Create a sub-package for scripts and move importer into it.
Move `measure-service-accuracy` script into new scripts sub-package.
Move the initdb command into new scripts sub-package.
Add XCTO and XXSSP security headers.

An explanation of these headers can be found at:
https://www.owasp.org/index.php/List_of_useful_HTTP_headers

The new stooge web service from Mozilla's security team checks for
the presence of these headers.
Include setproctitle, so celery processes are easier to distinguish.

Instead of all of them being called `celery`, they now distinguish
between the beat, worker main process and individual worker processes.
Pin down importlib, which gets pulled in as a dependency under Python 2.6.
added a "make shell" target to spin up ipython with a db and a session already configured to talk to the test database. Handy for poking around.

added a chunksize configuration option for S3 backups so that sqlalchemy doesn't fetch all rows into memory when journalling a backup file

first crack at reworking smaller tasks for S3+SQL backups

reworked the s3+sql backup tests so that zip files are logged through
heka

refactored the s3+sql backups again so that smaller subtasks are
scheduled when the write_measure_s3 task is invoked.