Add more examples on transformations

[jackdbd]

See these examples in Cairo and PyCairo:

• https://zetcode.com/gfx/cairo/transformations/
• https://gist.github.com/bert/1164354/75fd53542bc6fda77d22c435e349ee5f96ced1e7
• https://zetcode.com/gfx/pycairo/transformations/