Constructs placeholders

This is just so I don't forget this approach
to constructs. I may not even use this; it may
or may not be useful for 'Engine Builder' when
I get to that point.
Revised the roadmap

Now that the strategy for Otrera has changed,
much of the ROADMAP.md is unnecessary and/or
innacurate.
Rewrote some details and removed 'Analytics'

Analytics is still a big gray area.