Adds a Settings struct for creating parsers/commands with
NewParserWithSettings or NewCommandWithSettings.

Settings
	HelpDisabled -	defaults false, set true to not generate a help
			argument for parser/command
	HelpSname -	short name for the parser/command help argument.
			Can be left empty
	HelpLname -	long name for the parser/command help argument.
			Leaving empty forces use of -h/--help when
			HelpDisabled is false
	NoExitOnHelp -	defaults false, set true to not exit on help
			argument being parsed

Should resolve all outstanding help argument issues.

Fixed merge conflict error due to check function return type change confusion.

Added functions:
	DisableHelp
	SetHelp
	ExitOnHelp

Added Command.exitOnHelp

Added more tests to increase code coverage