feat(app): new options attribute

Fixes #10

Allows specifying options via `masonry` or `masonry-options` to avoid name
clashes with other directives.

BREAKING CHANGE: Options can no longer be specified via the `options` attribute.

Before:

<masonry options="{my: 'option'}"></masonry>

After:

<masonry masonry-options="{my: 'option'}"></masonry>
v0.4.0