The class provides parser of commandline options with built-in help created from a description of the options. It also provides default values for options not set on commandline.
initialize(short_name,long_name,argument,description,default = :nil,type = :string)
short_name: short form of the option, for example "-o"
long_name: long form of the option, for example "--option"
description: brief description of the option that appears in the help
default: value provided to the program when the option is not set from commandline. If the option must be set by the user, use CommandLine.check_compulsory to raise error when the option is not found.
Creates the CommandLine object from array of CmdLineOptions. The commandline is parsed, default values are used where not provided. If -h option is found, help is displayed and the program is terminated.
Goes through array of strings (option's long_name) and terminates with error if they are not present in the commandline
Fills the object with options from the list, parsing the commandline.