Example needs rename to include lib name

[kattni]

Example screenshot_simpletest.py should be named bitmapsaver_screenshot_simpletest.py to fit with CircuitPython library standards and clarify which library it is associated with in the example bundle.

The lines including this file name in the docs/examples.rst file must also be updated to reflect the name change, e.g.:

.. literalinclude:: ../examples/current_file_name.py
    :caption: examples/current_file_name.py
    :linenos:

would be updated to:

.. literalinclude:: ../examples/current_file_name_changed.py
    :caption: examples/current_file_name_changed.py
    :linenos:

[evaherrada]

Solved by #6