Elementspath entries should not be dragable

[Marek Lewandowski]

Buttons in elementspath should not be draggable. Now you can drag it into editable. What's worse in IE10, IE11 it will cause following exception:

SCRIPT5009: 'CKEDITOR' is undefined 
replacebyclass.html, line 355 character 1

1. open any sample with CKEditor (i.e. samples/replacebyclass.html)
2. click somwehere inside editable
3. click move body elements path part into editable

additional info:

1. it should be easily fixable with setting onmousedown="return false" on anchors

[Jakub Ś]

What's worse in IE10, IE11 it will cause following exception

I was only able to get this exception after clicking on link that was created after dropping body elements path into editable.

Problem can be reproduced from CKEditor 3.6.3 (when support for IE10 was added) but I'm setting version to 4.0 beta as it is going to be fixed in CKE 4.x.