As part of T603, the CLI should send a title parameter with posts.
This functionality is delegated to WF/Write.as clients to handle.
Like the web editor, we should assume the title is given only when a post begins with a Markdown H1, e.g.
# Title Body
(in this case, the title is Title.)
We already have a shared helper function that provides this capability: [posts.ExtractTitle()](https://godoc.org/github.com/writeas/web-core/posts#ExtractTitle) in the web-core package.