Wrong title of Floatingpane in Dock

[guest]

Create a Floatingpane and change the title with

myFP.setTitle("my new title");

Now when you dock (minimize) the floatingpane, the old title is displayed in the dock, because function

setTitle: function(/* String */ title){
		// summary: Update the string in the titleNode
		this.titleNode.innerHTML = title; 
	},

forgets to change this.title = title. The dock-title is computed from this.title.

[dante]

(In [12002]) fixes #5565 - and some cleanups