Accept "Message-Id" in addition to "Message-ID"
Add encoders from Trojita
Use Trojita encoders to format messages for sending

GMail will rewrap headers for us, so we don't need to worry about line
length there.  Thus, we make a change to the RFC 2074 encoder from
Trojita to not worry about line lengths when deciding if a header needs
to be encoded.

Refs #6.
Set From when sending emails

Closes #6.
Strip new lines from end of displayed messages

Also, make sure all font tags are closed.
Don't display drafts

We lack the ability to edit them.
Unescape &amp;
Add button to change unread status

Although we can get that with the info from the query, we fetch it with
the body request.  This way, it gets updated when we refresh the preview
after clicking the button.  It's not a perfect approach, but it's the
best I've found so far.

Closes #3.