Context sensitive insertHtml

[Garry Yao]

We've seen various paste problems caused by our current implementation of CKEDITOR.editor::insertHtml, now rely on browsers'native API, which is buggy, while we do have other option here: The idea is to implement an DTD aware, context sensitive insertion based on CKEDITOR.htmlParser' and 'CKEDITOR.editor::insertElement', this should be able to extinguish all weird bugs around.
Related tickets are:

#5170

Problems with pasting (executing insertHtml) and formatted text

#5030

CKEDITOR.timestamp wasn't added while loading skin.js

#4898

Paste: After pasting a table from word it is not possible to navigate outside the table

#4746

insertHtml left trim text

#3105

insertHtml and insertElement should agree on the result

#2781

FckEditor InsertHtml inserts extra <p> tags

#2749

InsertHtml() is inconsistent between IE 7 and Firefox 2

#2526

InsertHTML Problem

#503

Unordered list paste: doesn't work correctly in IE