Remove .gitattributes.
Allow `== null`.

`== null` is useful. It covers the case of `null` _and_ `undefined`, the
alternative being `=== null || === undefined`.
Change indent spacing to 4 spaces.
Change bower install dir to "app/vendor"
Use angular-bootstrap instead of jquery.
Change build dir to "build"
Add in environment configuration.
Add deploy scripts.
Fix interpolation in Gruntfile template
Fix useminPrepare task to rewrite relative CSS urls

First, tell useminPrepare to only 'cssmin' our CSS files (dropping the
concat task). See https://github.com/yeoman/grunt-usemin/issues/225.
Second, tell cssmin to rewrite relative urls to be relative to our app
directory.

This is particularly useful for bower install components that have CSS
files that reference relative urls. ie.

```
.
├── app
│   └── bower_components
│       └── component
│           ├── images
│           │   └── image.png
│           └── style.css
└── build
```

```
body {
background: url('images/image.png');
}
```

Will have now properly rewrite it's image url to
```
body {
background: url('bower_components/component/images/image.png');
}
```