Version 1.5.1: Access

This patch release adds better access to the App progromatically, to assist with writing custom converters to other formats. It also improves the help output, and uses a new feature in CLI11 1.5 to fix an old "quirk" in the way unlimited options and positionals interact.

• Make mixing unlimited positionals and options more intuitive #102
• Add missing getters get_options and get_description to App #105
• The app name now can be set, and will override the auto name if present #105
• Add (REQUIRED) for required options #104
• Print simple name for Needs/Excludes #104
• Use Needs instead of Requires in help print #104
• Groups now are listed in the original definition order #106