Enable automated testing on PyPy 3
Added support for Drawing.polygon, Drawing.polyline, and Drawing.bezier.

 - Created PointInfo struct reference in API type casting.
 - Assigned / mapped arguments for Draw(bezier|poly(gon|line)) library method.
 - Completed initial unit test & documentation.
Updated docs with usage of new methods, and added `versionadded` docstring
Bumped versionadded number (my mistake) on new Drawing methods.

 - See comment: https://github.com/dahlia/wand/pull/192#issuecomment-55516320
Add default value to Font.size
Suggest libmagickcore5-extra package for delegates
Skip if non-Unicode filesystem encoding.  Fix #193

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=761325
Added Drawing.fill_rule property to allow control over complex shapes (e.g. polygons with holes)
Mapped C-API methods for additional drawing shapes

 - Arc
 - Circle
 - Ellipse
 - Point

Light refactoring of docs & method signature order.
Fixed light typo in docs