Snap options can be defined in the angular's config phase

Allow to define options in a lower level, in the config phase, like so : 

```javascript
angular.module('myApp', ['snap'])
  .config( function( snapRemoteProvider ) {
    snapRemoteProvider.globalOpts.disable = 'right';
    // or
    snapRemoteProvider.globalOpts = {
      disable = 'right',
      // ... others options
    }
  })
```

Add the ability to define global Snap options into angular config phase.
The main goal is to define global options in a global area and not necessarily in a controller. The latter solution still works and overwrite options defined in the config phase.

No breaking change, unit tests added.