Py-toolbox

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- added ``schedule`` module for scheduled task execution

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- added ``safe_copy`` parameter to ``named_product``

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- added ``render_outputs`` option to ``Notify``
- added ``render_text`` function

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- added ``itertools`` module with ``named_product`` function
- added ``after_every`` parameter to ``Notify.on_iteration_of``

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- added on_iteration_of method to notification module
- removed 3.8 and nightly python versions from travis build bacause those
versions are broken for pylint
- added type parameters to all modules and mypy to check types statically
- fixed error in _run_mainsave contextmanager in RDB module
- added pylint for static code analysis as build step and refactored code to
pass analysis

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- fixed an error when importing importlib while no ipython is available
- updated dev requirements
- enabled automated CI with travis