* Used calls to super() for __init__ subclasses
* using the module's get_instance
* Moved the get_plugin to the module itself to handle singleton
* split_label is now more complicated to handle the up arrow for error
printing
* Added a is_interactive, as cmdloop vs onecmd don't handle a non-zero
return
* Worked on default, the main switch to analyze the line and dispatch to
commands
* emptyline is overriden
* Each keyword traversed at command insertion adds the plugin to it's
list
* get_sub_keywords_keys can handle a scope (for future "use" command)
* get_matching_prefix main function to match a prefix with a list of
labels