Update the Masonry JavaScript library to version 3.

The new script handle is 'masonry'. The old 'jquery-masonry' handle is the official shiv that sits on top of the v3 library. While v3 no longer depends on jQuery, a theme or plugin may have bee
n implicitly loading jQuery though Masonry, rather than additionally declaring it as a dependency for themselves. Thus, the shiv is separate.

Themes should switch to 'masonry' and declare jQuery as a dependency on their own if they need it. Upgrade guide: http://masonry.desandro.com/appendix.html#upgrading-from-v2. imagesLoaded remai
ns included with Masonry here.

props shelob9.
fixes #25351.

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git-svn-id: https://core.svn.wordpress.org/trunk@27127 1a063a9b-81f0-0310-95a4-ce76da25c4cd