Re-order the "Authors" box on the calendar

[stevejburge]

This makes a lot of sense:

We're using PubishPress' calendar to add new posts during our editorial meetings. As you know clicking on a day of the week a little pop up appears to quickly create a new post. The first field is the Author field. In a blog with multiple authors (where PublishPress shines) the list defaults to the first user name alphabetically. This field should default to the current logged in user instead. What happens is we have an editorial meeting where we discuss upcoming news and start plopping in placeholder pitches to help plan out the next two weeks, but users ignore that field as we run through the backlog of ideas. Then we have a bit of confusion when a bunch of posts get attributed to user "Aardvark" instead of the person who was adding the post.

Ideally we should move to some kind of select box here to avoid very long-dropdowns and to work with "Multiple Authors"