* Add ability to inject statsd client; some py test/reqs updates
- Updated the metrics logger to allow construction with an existing
statsd client, so that it can be configured by external systems or libs.
- added requirements to requirements-dev.txt which are needed to run
tests-eg coverage, nose
- removed dependency on mock lib, it is in python stdlib now
- updated tox.ini to remove the now-superfluous deps
* add license to test file, and remove blank line at EOF
* [scheduled reports] Add support for scheduled reports
* Scheduled email reports for slice and dashboard visualization
(attachment or inline)
* Scheduled email reports for slice data (CSV attachment on inline table)
* Each schedule has a list of recipients (all of them can receive a single mail,
or separate mails)
* All outgoing mails can have a mandatory bcc - for audit purposes.
* Each dashboard/slice can have multiple schedules.
In addition, this PR also makes a few minor improvements to the celery
infrastructure.
* Create a common celery app
* Added more celery annotations for the tasks
* Introduced celery beat
* Update docs about concurrency / pools
* [scheduled reports] - Debug mode for scheduled emails
* [scheduled reports] - Ability to send test mails
* [scheduled reports] - Test email functionality - minor improvements
* [scheduled reports] - Rebase with master. Minor fixes
* [scheduled reports] - Add warning messages
* [scheduled reports] - flake8
* [scheduled reports] - fix rebase
* [scheduled reports] - fix rebase
* [scheduled reports] - fix flake8
* [scheduled reports] Rebase in prep for merge
* Fixed alembic tree after rebase
* Updated requirements to latest version of packages (and tested)
* Removed py2 stuff
* [scheduled reports] - fix flake8
* [scheduled reports] - address review comments
* [scheduled reports] - rebase with master
