Fix for masorny not load pre WP 5.3

[spacedmonkey]

Summary

In UVP-178 it was noted that the the masonry view ( using the macy library ) is not loading loading. Looking into the issue more, it seems like the masonry was loading on site running WordPress 5.3 and above. This is because the our code uses a trigger ( backbone event / hook ), to trigger redraw of the masonry called attachments:received. The trigger was only added in 5.3.

In this PR, I simply back port two method that implement this trigger.

Fixes UVP-178

Checklist

• [ ] My pull request is addressing an open issue (please create one otherwise).
• [ ] My code is tested and passes existing tests.
• [ ] My code follows the Contributing Guidelines (updates are often made to the guidelines, check it out periodically).

[spacedmonkey]

@derekherman This really need to be Alpha IMO.