Change Django settings prefix to EVENT_TRACKING

This will prevent conflicts with the existing edx-platform settings.

Change-Id: I0ea1a2b19d1097963a9faead43b7aa0480c41ef2

Small doc change.

add python logger backend

Change-Id: I524111d77e1c13bd70aa75088f199c6e294489db

support event processors

rename event_type field to "name"

Cleanup mongodb authentication

Authenticate to the database before getting a reference to the
collection.

ensure all packages are added to the egg

remove the sample django middleware from the project

It was basically serving as an example, however, that can be included in the docs (or not at all).  Actual usage of this middleware was cumbersome since it is effectively frozen in the library.  It is expected that most people would want to customize this behavior dramatically.

fix build errors on read the docs

update design doc, support building docs

put back in the context manager

change calling convention from verb-noun (track.event) to noun-verb (tracker.emit)

support nested event contexts

* Support registering nested contexts
* Provide basic Django middleware for tracking requests

* Infrastructure for running performance and integration tests
* Basic tests of both types for the MongoDB backend
* Ensure timestamps include tzinfo

Uses "make" to simplify the execution of the various commands.  We could probably integrate with manage.py or setup.py or something more sophisticated in the future if necessary.  For now I wanted to KISS.

Update AUTHORS file

    * Create a skeleton Django project so that we can run tests that make use of Django settings etc
    * Move the Django specific backend construction logic to a django package
    * Get rid of global (module level) state, allow tracker instances to be created ad-hoc (similar to logging)
    * Improve API and extensibility

add support for travis ci

fixed RST formatting of roadmap list