block links and forms when edit mode is on

This allows editing links and submit buttons. Clicking the text to edit it, would result in a redirection or form submission. This fix would prevent opening a link or form submission while in edit mode.

Important to note, it's (probably) impossible to block all events (think off a button that activate a popup), but this would fix at least the most common scenario: external links and (regular) form submissions.

If you load phrasing js before anything else in your application, then any extra jquery click handler on links or form submission will be blocked by stopImmediatePropagation (since phrasing binded first, thus it would not propagate to the other event handlers).

example:
````
 $('a:not(#phrasing-edit-mode-bubble a)').on('click', block_events);

// this event is blocked
$('a').on('click', open_popup)
````

So in this case, sequence of binding matters.