The Create Page dialog makes too many HTTP requests for page name cleanup

There are two issues:

• a new HTTP request is made on each key stroke on the title input; it's enough to keep a key pressed to flood the server with requests
• a new HTTP request is made whenever the title input looses the focus, even if you don't change the title
• an HTTP request is done even for the empty string
• in general, a new HTTP request is done even if the title didn't change