Compatibility Update with WP 5.x + Bug Fixes

This is a large change to merge in and release a longrunning set of code updates to make the Gutenberg codebase compatible with both WP 4.9 (Gutenberg Plugin) and WordPress 5.x after Gutenberg was moved into Core. For instance all code that calls the editor had to be updated to to account for the changes made to the editor to make it more modular in core.

• Fixes editor side column classes for photo essay, photos now sized correctly
• Merges long running branch(s) to update plugin codebase to support upgrade to WP 5.x. from Jeremy Felt.
• Fixes error causing posttext,pretext format api formats to appear on all toolbars after update branch changes. #222