Shady ondemand fixes

[sorvell]

• adds ShadyDOM.validateNodePatch which can reset a patch on a node if needed.
• can specify ShadyDOM.onDemandPatches, a list of properties to always patch when in on-demand mode.
• always patches styling related properties (setAttribute, className) on elements
• allows a limited form of overriding native methods in custom elements by copying implemented methods to the "native" version

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.