Capitalize "Armstrong" and change command name to something easier and more obvious.
Make the CLI entry point a little more flexible.
WIP switching from Fabric to Invoke. Task arguments are currently broken as Invoke parses them differently and cannot handle arbitrary args/kwargs.
Use Decorator to create our own decorators to allow the "real" function signature and argspec to bubble up to @task.
Invoke needs this "real" information to create the CLI arg options. Invoke cannot parse arbitrary args/kwargs so we can't do it the easy way like Fabric 1.x allows.
Handle Invoke task args. Fabric could handle arbitrary args/kwargs, but Invoke can't.
Fix `--extra` handling for kwargs.  Now things like `--extra "test1 test2 --verbosity=0"` work.
help test for Invoke tasks
Merge branch 'invoke' into v2.0-prep
Django 1.6 uses the native 1.6 test runner.
Override and use the Django 1.6 test runner and backport for older Djangos.

The new Django test runner "will discover tests in any file named “test*.py” under the current working directory". Previously the "test runner only discovered tests in tests.py and models.py files within a Python package listed in INSTALLED_APPS".
This means we can drop `TESTED_APPS` because the runner no longer tests everything in INSTALLED_APPS. That's much easier and worth backporting for just to simplify our code.
It also standardizes on the new way so you don't have to remember which Django version is installed when testing your Armstrong component.
Finally this opens the door to moving the tests directory and not shipping it. (Well, it's one easy way to make that change.)

But we don't use "test*.py" files, we use a `tests/` package. Overriding the runner with this one line change seemed easiest. Easier than passing in a "pattern" kwarg or injecting "--pattern" into our pseudo CLI command launcher.
Relative package import of renamed file.
Packages - make Invoke optional.

Invoke isn't *really* optional for development but it *is* for testing. So in favor of even faster test virtualenv building, don't install Invoke. Tests can be run with `python -m armstrong.dev.django test` (instead of `invoke test`).
The readme will be updated in a separate commit with a few different things, but in essence a dev environment will need `pip install tox invoke -r requirements\dev.txt`.