Add Rich Text Support to Composition Tool

Composition Tool is a great idea; love being able to write (and collaborate) and send it directly to a draft on our blog, but there's no support for rich media (i.e. YouTube videos and other embedded items). 


These are quite common in modern blogs and not being able to add them in the composer, creates a huge inconvenience. 


I'd love to see more HTML options be made available so that we can actually draft an article exactly as we want it to appear when live -- basically the blog editor but with sharing, commenting, and other collaboration elements.