define:nimPreviewProcConversion compatibility
Add a preview compatibility in case someone has aggressively forward-thinking nim.cfg's. Bump minor.
This could go to 1.0.0 - I have been using it dozens to hundreds of times per day for 4 years (to this very date!) with no real trouble.
Major 1.0 should, however, probably wait until possibly cleaving cligen/magic
into its own package -- just about the easiest part of c-blake/cligen#201