Bind missing events

[live627]

The supported events are:

• 'keyup`
• 'keydown`
• 'Keypress`
• 'blur`
• 'focus`
• 'input`
• 'nodechanged` - When the current node containing the selection changes in WYSIWYG mode
• 'contextmenu`
• 'selectionchanged`
• 'valuechanged`

What this PR does

Adds callable events that were only accessible via "signals"

• pasteraw
• paste
• pastehtml

Goal

To eventually replace signals with events. I believe the concept of event listeners is easier to grasp since everything in the JS world uses them.

Question

Should we go one step further and make init() and destroy() events too?

[live627]

Just noticed that those "missing" events are bound to the editor's containing div. Is that a roundabout way to use CustomEvent from the DOM?