Semantic versioning and version releases

[idcrook]

starting at 0.1.0 and going forward.

Used by Cooapods, SPM, etc.

[idcrook]

part way there.

DRY has this number being maintained in .podspec file and snarfed into other places it's needed.
will tag semvar vMAJOR.MINOR.PATCH. (ex. V0.1.0)