Working towards own Bézier classes for all contexts.

Stability release.

Should fix issue #207 (still doesn't run on Windows).

First real release, still testing but most of the basic examples in the PageBotExamples repository are working as expected for both the DrawBot and the Flat contexts.

Smoother context detection, defaults to Flat if pagebotcocoa is not available.

Adding flat requirement tot setup.

New version for RTD documentation generation.