User should be able to change the font of new and existing posts.
Drafts (new and existing) should save the post's current font along with the post content. New drafts should change the editor's default font when the font is changed, i.e. the editor should retain the last-selected font as the default font for subsequent new posts.
Header bar should have a (disappearing on non-hover) font icon with a down arrow next to it. Hovering over this shows a list, similar to the Publish To list, with the names of each font in it's respective font face:
* Serif (`norm`)
* Sans-serif (`sans`)
* Typewriter (`wrap`)