Fixed editor crash after deleting a table.

This is a fix for a bug.

*Scenario:*
1. Have an inline initialized editor
2. In that editor add a table and ensure that it is the sole element in the editable container (nothing before and nothing after)
3. Use the contextual menu to delete the table
4. The editor is no longer working :(

Note: This can be reproduced also on the demo site: http://ckeditor.com/demo#inline

*The fix:*
Just added a check to not remove the parent element of the table if that parent is the container.
Used editable instead of container.
Added tests for removing table directly in inline editor.
Minor changes, use node#equals to check if parent is an editable.
Improved table tests.
Tests don't verify whether wrapper is really removed.
On older IEs we must expect nbsp instead of br as a filler.
Changelog entry.
Merge branch 't/12110'
Merge branch 'master' into major
Hide (with display:none instead of left offset) drag handler in order to not extend widget's outline.
Changelog entry.
Merge branch 't/12024' into major
Added missing changelog entry.
Enabled widgets' commands inside nested editables.
Changelog entry.
Merge branch 't/12112' into major
Fix for bug #11897.
Tests: Added tests for enter key in empty list item with format.
Changelog entry.