v6.0.0 (30 October 2013)

Changelog:

• Added: Open path (polyline) clipping. A new 'Curves' demo
  application showcases this (see the 'Curves' directory).
• Update: Major improvement in the merging of
  shared/collinear edges in clip solutions (see Execute).
• Added: The IntPoint structure now has an optional 'Z' member.
  (See the precompiler directive use_xyz.)
• Added: Users can now force Clipper to use 32bit integers
  (via the precompiler directive use_int32) instead of using
  64bit integers.
• Modified: To accommodate open paths, the Polygon and Polygons
  structures have been renamed Path and Paths respectively. The
  AddPolygon and AddPolygons methods of the ClipperBase class
  have been renamed AddPath and AddPaths respectively. Several
  other functions have been similarly renamed.
• Modified: The PolyNode Class has a new IsOpen property.
• Modified: The Clipper class has a new ZFillFunction property.
• Added: MinkowskiSum and MinkowskiDiff functions added.
• Added: Several other new functions have been added including
  PolyTreeToPaths, OpenPathsFromPolyTree and ClosedPathsFromPolyTree.
• Added: The Clipper constructor now accepts an optional InitOptions
  parameter to simplify setting properties.
• Bugfixes: Numerous minor bugs have been fixed.
• Deprecated: Version 6 is a major upgrade from previous versions
  and quite a number of changes have been made to exposed structures
  and functions. To minimize inconvenience to existing library users,
  some code has been retained and some added to maintain backward
  compatibility. However, because this code will be removed in a
  future update, it has been marked as deprecated and a precompiler
  directive use_deprecated has been defined.