v2.12.0
Fixed some file permissions (Cygwin loves adding execute)
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Fix #297: Unrendering fails when replying to (visible) MDH email
Added class name to math image element. Refactored options defaults.
Added tests for some newly exported Utils functions: walkDOM, utf8StringToBase64, base64ToUTF8String, rangeIntersectsNode. Also found bad behaviour in Chrome's Range.intersectsNode, so now we're only using the fail-back code.