[Bugfix - MED] Fixed the private messages reply button

Well, I ended up creating a simple pull request after all. It seems the reply button is not working because of the return value of the *onclick* event. Without using jQuery, and keeping the event handling in an inline JS, I guess the *return false* is the way to go. However, I'm not 100% sure it will work on all browsers. So far I can confirm it works on Chrome 36 and FF 31.

Source: http://www.question2answer.org/qa/37596/reply-in-to-private-messages-in-alpha-2-1-7