Django-arcutils

- Made the masquerade app more RESTful. In particular, it's now possible
to request a JSON response from its select (user) view. Because of
this, the user data it returns is now serialized using a DRF model
serializer; I don't think this will cause any backward-compatibility
issues, but it might.

- Added support for Python 3.6.
- Started adding support for Django 1.11.
- Upgraded DRF 3.5 => 3.6.
- Removed default `STATICFILES_DIRS` local setting. This isn't needed in
the case where `arcutils` and the project are in `INSTALLED_APPS`--
which is the common case--since static directories in apps are
included by default.
- Added custom `collectstatic` Django management command with
`--exclude` and `--include` options. Unlike the built in `--ignore`
option, these match against whole paths instead of path segments. In
addition, if a file is `--include`d it will be included even if it was
previously ignored or excluded; this is useful when ignoring a big
directory like `node_modules` that contains a file or two that should
be included (e.g., `almond.js`).
- Updated tasks/commands for latest version of ARCTasks.

Major Changes

- Reimplemented `settings.get_setting()` and `PrefixedSettings` so they
use django-local-settings' dotted item functionality internally. This
makes these simpler and more consistent with other settings access in
ARC/WDT projects. The major external difference is that a `KeyError`
will be raised now instead of a `SettingNotFoundError`. In addition,
it's now possible to traverse into settings values.
- Enhanced group handling in `UserMixin`. Groups can now be `Group`
objects in addition to group names. This was copied over from ohslib
so that ohslib could use ARCUtils' `UserMixin`.
- When Django 1.10 is in use, the `MIDDLEWARE_CLASSES` setting is now
automatically removed from settings (assuming the `MIDDLEWARE` setting
is present and set).
- Added `settings_processors` option to `settings.init_settings()`. This
makes it easy to modify settings if needed.

Other Changes

- Upgraded django-local-settings 1.0b3 => 1.0b5.
- Upgraded tox 2.5.0 => 2.6.0.
- Improved tox.ini; in particular, test each version of Python in order,
and each version of Django in order for each version of Python.
- Started adding support for Python 3.6 and Django 1.11 (the latter is
still in alpha).
- Added `<package>.staging.rc.pdx.edu` to default stage `ALLOWED_HOSTS`.
- Added `show_upgraded_packages` task from ARCTasks.
- `settings.init_settings()` now returns the `settings` dict its passed.
This seems like it could potentially be useful, whereas returning
`None` isn't.

- Added `findunusedtemplates` Django management command (works pretty
well but could be improved).
- Added `showsettings` Django management command.
- Set default database for dev and test to `localhost`. This is intended
to be more reliable than depending on a local socket connection. It's
also more compatible with some Docker setups.
- Improved `wsgi.py` by allowing the root and virtualenv directories to
be specified via the `WSGI_ROOT` and `WSGI_VENV` environment
variables. This is another change supporting Docker setups.
- Added `redirect_location` template tag, which is a wrapper for
`response.get_redirect_location()`. The former is much easier to use
in templates versus adding a var to the template context in the view.

- Added basic Sentry support. Added raven (Python Sentry client) to
dependencies and added `raven.contrib.django.raven_compat` to
`INSTALLED_APPS`. This makes the assumption that we (eventually) want
to use Sentry in all (or at least most) projects.
- Updated default dev and test settings to use package name as database
username instead of defaulting to the current OS user. This goes with
a corresponding change in ARCTasks that creates a database user named
after the package when creating databases.
- Upgraded ldap3 1.x to 2.x (1.4.0 => 2.1.1). This required a few
tweaks, but the ARCUtils LDAP API is essentially unchanged.
- Upgraded DRF 3.4.x => 3.5.x. This is used only in dev and testing.
- Added default DRF renderer settings for all environments. These
defaults are based on the notion that most projects will have an
(Angular?) front end talking to a RESTful back end. Proposed by
conwayb.
- Improved `require_block` template tag. Made it more flexible with
regard to the path prefix for `require.js` or `almond.js`. The
`ARC.require_block.prefix` setting can be used to override the default
`vendor` prefix.

- Made all middleware compatible with Django 1.10 and above. Did so by
reimplementing all middleware for Django 1.10 and then adding shims
for Django 1.9 and below.
- Added `drop` arg to `init_settings()`; this allows projects to drop
unused, cluttering settings.