There are four assistant roles:

.. note:: Please be advised that with version 0.10.0, the ``modify`` command
          changes to ``tweak``.

creator (``create`` or ``crt`` on command line)
  creates new projects
modifier (``modify`` or ``mod`` on command line)
  works with existing projects
preparer (``prepare`` or ``prep`` on command line)
  prepares environment for development of upstream projects
task (``task`` on command line)
  performs arbitrary tasks not related to a specific project

The main purpose of having roles is separating different types of tasks.
It would be confusing to have e.g. ``python django`` assistant (that
creates new project) side-by-side with ``eclipse`` assistant (that registers
existing project into Eclipse).
