- Plugins now only present a get_commands method taking the parser to
populate as argument and returning an iterable with which the cmds
dictionary is updated (i.e. the plugins returns the command callbacks).
- The name attribute in plugins is now a class attribute.
Applied the corresponding changes to command files.
AMakes it possible to declare and use additional parser inside subparsers.
May be useful for tag command. Will be implemented in texnote plugin.