Document the 1.2/1.4/1.6/2.0 branch layout in README
Document the 1.2/1.4/1.6/2.0 branch layout in README
Add a bash-completion-generator example built on ArgModel
Add ArgGroupModel: group-aware ArgModel, replacing the flat-only shape
Drop the get prefix from getters: getArgList() -> argList(), etc.
Restore explicit guidance on SpecificationException in the manual
Remove StdOutput.h's dead removeChar; drop ArgTraits.h's needless virtual dtors
Demonstrate Arg::Callback (.onMatch) via a new example and unit tests