Fix #215 "Cannot remove the last author once post is saved"

Problem: "If you assign a co-author to a post, save it, and reload the page, the Remove link disappears. You can no longer remove that author."

Fix: Remove the comment // Hide the delete button if there's only one co-author and the two lines of code that follow. The lines in question hide the "X" button. Removing those lines means the X button stays, allowing users to remove the last author.