[AndyB] Start direct message 1.0

Start direct message from post.

When the Start direct message link is clicked, it will automatically add the thread title and quote the post in the direct message. This allows the direct message recipient to quickly know which post the direct message is about.

(Example of Start direct message link)





(Example of starting a direct message)





(Example of Options page)






Features:

• All phrases start with startdirectmessage_ for your convenience.