Tests: Created test for CKEDITOR.dom.documentFragment#getHtml.
Tests: Fixed code style of CKEDITOR.dom.documentFragment tests.
Tests: Added basic tests for editable#extract/getSelectedHtmlFromRange().
Tests: Renamed test file to match API.
Tests: Extended coverage for editable#getSelectedHtmlFromRange.
Tests: Additional tests for bogus BRs.
Various improvements of editable#getSelectedHtmlFromRange.
Tests: Updated and extended tests for editable#getSelectedHtmlFromRange.