Allow generated JS to define new angular module

This commit allows the module option to be an object literal as well as a string. When defined as an object literal we can specify that a new angular module should be defined.

```js
ngtemplates:    {
  myapp:        {
    options:    {
      module: {
        name: 'templates',
        define: true
      }
    },
    src:        'src/views/**.html',
    dest:       'dist/templates.js'
  }
}
```

This generates the following.

```js
angular.module('templates', []).run(['$templateCache', function($templateCache) {
  ...
}]);
```

Commit includes full test coverage and README updates. Let me know if you have any concerns or change requests.