* add some tests with default capture on the two parameter template and some notes about it in the README.md
remove the test from visual studio 2015
vs2015 doesn't seem to properly deal with is_assignable in the cases we care about so make a standalone version that is more direct in what we are doing
add version to appveyor and add some notes to the readme
fix a few test cases to make sure code is covered and test a few other paths
remove unneeded enum streaming operator
add some diagnostic escapes around trait code to eliminate gcc Wnarrowing warnings
work specification of the template operations
remove optional add some templates for options conversions
add the two parameter template for add_option
* Fix some comments from Code review and add more description
* fix case when string_view doesn't work to append to a string.
* This PR also addressed #300
* modify lexical_cast to take const std::string &, instead of by value to allow string_view in a few cases
in progress: formatters
Getting closer
Working on apps
One test actually runs
All builds, added filter functions
Reverting a few behavours as needed
Repairs
All tests pass
Fixing error with adding help flag
Labels are simpler mappings, normalized setters
Adding help_all
Adding a few more tests
One more line tested
Adding one more check
Adding to readme
Simplify naming
Adding default constructors
Fixing spacing issues with subcommand all printout
Adding a couple of tests
This mostly is cleanup, with fewer alternative methods and more standard syntax, avoiding the use of the namespace all the time. Validators are simpler and are added through `->check()`.
Defaults are automatic, and can be specified with a final arg to the options.
Expected arguments and required arguments are now accessed through a pointer to option.
Option now can be checked as a bool to see if the argument was passed.
Errors have better organisation.
