8.1: Add a command line option to load the calculator extensions dynamically; e.g., a command line could be ”extension=myclassfile. Note that multiple extensions could be specified. You'll need to figure out the exact nature of how to specify multiple extensions.
8.2: Add a command line option that specifies an XML configuration file used to define which extensions should be loaded dynamically. Remember that any command line option other than the configuration option must be available as an option in the configuration file.
8.3: Enable logging in the entire calculator application. Remember to include different levels of logging capabilities that a command line option or a configuration file defines.