Subtle changes, bugs and feedback

I have just made it so that:

• You cannot SHOUT in unicode... that is, if you type in a Chinese script in title case then we will convert it to all lower case (or equivalent). Works for all languages, and applies to text of posts as well as titles and usernames.
  
• You can no longer use any non-printing characters on the site. Only spaces, tabs and newlines are preserved, and even then only where it makes sense to. Specifically usernames are words, they can contain no space whatsoever, even unicode spaces are removed.