[Feature Beta] Expose uuid

I noticed that UUID is going to disappear from the publicly available API when 1.7 ships and I'm dependent on generating UUIDs for an i18n attribute helper.  Because I have accessibility and localization requirements that require me to fully support interpolated attributes I had to develop a helper.  The implementation is very similar to `bind-attr` which requires generating a data-bindattr wiht a uuid. I realize that this may go away when the metal-views branch gets merged but for the time being I don't see any problem in re-exposing it as it already is exposed in 1.6.1.