- relax casting rules
* down-cast of labelToken to boolToken
* up-cast of wordToken to stringToken.
Can use isStringType() test for word or string types
- simplify constructors, move construct etc.
- expose reset() method as public, which resets to UNDEFINED and
clears allocated storage etc.
DEFEATURE: remove assign from word or string pointer.
- This was deprecated 2017-11 and now removed.
For this type of content transfer, move assignment should be used
instead of stealing pointers.
- use succincter method names that more closely resemble dictionary
and HashTable method names. This improves method name consistency
between classes and also requires less typing effort:
args.found(optName) vs. args.optionFound(optName)
args.readIfPresent(..) vs. args.optionReadIfPresent(..)
...
args.opt<scalar>(optName) vs. args.optionRead<scalar>(optName)
args.read<scalar>(index) vs. args.argRead<scalar>(index)
- the older method names forms have been retained for code compatibility,
but are now deprecated
