Update thirdparty submodule.
[[ Bug 11748 ]] If replacing XML text node contents with empty, then just discard text nodes (don't try to insert a new one).
[[ Bug 12210 ]] Update revBrowser on Windows to use a different snapshot method from before (old one doesn't work in IE9+).
Merge branch 'bugfix-11748' into release-6.6.2
[[ Bug 11748 ]] Added release note.
Merge branch 'bugfix-12210' into release-6.6.2