Added setup to avoid copying code

### Need:
```gherkin
A as a developer
In order to use a 3rd party module in my application without having to copy code
I want to easily install/uninstall the module.
```

### Solution:
 - [x] Add a setup.py file making the superbulk view importable `from django_superbulk import superbulk`
 - [x] Update README with new setup instructions

### Prerequisites:
 - [How to setup a python module](http://docs.python.org/2/distutils/introduction.html#distutils-simple-example)
 - [Example of setups of other projects](https://github.com/toastdriven/django-tastypie)