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.
Merge branch 'master' into features/162-geosubmit