avoid dependencies for tests

[aewallin]

We now depend on a random-polygon-generator and on a font-geometry-source library for a lot of tests.
This is fine for development, but maybe not ideal for deployment and automated testing.

It would be better to use the geometry-sources to generate "hardcopy" text-files with the desired test-geometry and store that in each test-directory. A good descriptive text-format is needed (YAML/INI-format or similar?)

[aewallin]

this example shows how to write an ini-style text file with geometry from truetypetracer
https://github.com/aewallin/truetype-tracer/blob/master/py/test_3_textwriter.py

these could be included as plain-text files in tests, as source of geometry.

a similar format can be used for random polygons also.