Allow users to create discussion threads in addition to submitting links...

Here's my attempt at issue #64.

This change will allow users to create discussion threads ("self" threads, "Ask/Show *" threads, etc.) instead of posting links.

This commit does not include markdown (I assume markdown will be used for comments as well?) to keep the scope of these changes small.

There may be bugs here, But I wanted some early feedback to see if this feature was something that would be used or not. I believe It Works, but there is definitely some room for improvement...