Add ability to specify custom python requirements.

This lets you specify additional python packages to be installed
into the edxapp virtual environment.

The `EDXAPP_EXTRA_REQUIREMENTS` should be a list of dict objects
with `name`, `version` (optional) and `extra_args` (optional) keys,
that correspond to the options of ansible's pip module.

Example:

    EDXAPP_EXTRA_REQUIREMENTS:
      - name: mypackage
        version: 1.0.1
      - name: git+https://git.myproject.org/MyProject#egg=MyProject
Don't restart edxapp after updating on devstack

- when using `/edx/bin/update edx-platform (branch)`
Added Brandon DeRosier to authors
Merge pull request #1678 from edx/feanil/rc-lavash-0

Feanil/rc lavash 0
remote maintenance site.
Operationalize harprofiler.
Add s3 watcher plugin.

Here is an example vars.yml file to pass in when running the newrelic role
with s3watcher enabled:

  ---
      S3_ACCESS_KEY_ID: s3accesskeyid
      S3_SECRET_ACCESS_KEY: s3secretkey
      S3_BUCKET_NAME: bucketname
      AWS_REGION: us-foo-1
      S3_CONFIG_FILENAME: fooconfigfile
      NEWRELIC_S3_WATCHER: True
      NEWRELIC_LOGWATCH: False <--not a required var, but it's True by default
      NEWRELIC_LICENSE_KEY: "my_api_key"
adding override for OAUTH_ENFORCE_SECURE
move venv to subdir and activate it.
Merge pull request #1671 from edx/benp/new-relic-s3-plugin

new relic s3 plugin
Merge pull request #1680 from edx/e0d/maintenance-site

E0d/maintenance site
Merge pull request #1670 from mitodl/bdero/fix-devstack-edxapp-restart

Don't restart edxapp after updating edx-platform using script on devstack
Merge pull request #1682 from edx/jarv/default-for-oath

adding override for OAUTH_ENFORCE_SECURE
disable S3 watcher by default
Merge pull request #1683 from edx/derf/NEWRELIC_S3_WATCHER_set_default

disable S3 watcher by default
Merge pull request #1681 from edx/benp/harprofiler

Operationalize harprofiler.
Harprofiler repo is now under edx. Disable test cruft.

The test was under dev and shouldn't have been merged. (This
approach is incompatible with ansible's design.)
Merge pull request #1684 from edx/benp/move-harprofiler-ref

Harprofiler repo is now under edx. Disable test cruft.
Compiling Insights Translations
Merge pull request #1685 from edx/insights-translations

Compiling Insights Translations