Custom params for UI Bootstrap $modal.open

[tafel]

Description In the lightbox-service, the method Lightbox.openModal makes a call to $modal.open with some parameters.

I needed to be able to add other supported parameters for $modal.open ("size": "lg", for example).

This pull request adds a third parameter in the Lightbox.openModal method, so it's possible to inject other configuration params to $modal.open.

Usage

var images = [ /* list of images */ ];
    index = 1,
    // UI Bootstrap modal configuration
    modalConfig = {
        size: 'lg'
    };

Lightbox.openModal(images, index, modalConfig);

[compact]

Thanks!