created new base class argument
created new base class command
fixed bug in class argument
updated class command
fixed errors in implementation of class argument
derived class final_option from class argument
derived class commandline from class command
derived class subcommand from class argument and command
added type trait functionality
created class vector
derived class operand from class argument and vector
derived class option from class argument
derived class flag_option from class option
updated class operand
fixed errors in class option
updated parsing functionality in class flag_option
derived class value_option from class option
merged 'feature/core-classes' into 'development'