1.1.1

Changed the names of the user-settable variables in CMakeLists.txt, so
that they're all grouped together in ccmake.
* PYTHON_API is now OOFCANVAS_PYTHON_API.
* DESIRED_PYVERSION is now OOFCANVAS_PYTHON3_VERSION and only
  appears when OOFCANVAS_PYTHON_API is "Python3".
* DESIRED_SWIGVERSION is now OOFCANVAS_SWIG_VERSION
* SWIG_USE_BUILTIN is now OOFCANVAS_SWIG_USE_BUILTIN and is only
  available in advanced mode.

1.1.0

Replaced the distutils-based build system with cmake.

Now compatible with both Python2 and Python3.

Now compatible with swig 4.  Removed OOFSWIG.

Moved the body of oofcanvasgui.h to oofcanvas.h and removed
oofcanvasgui.h.  There's no need to make users keep them separate.

When creating CanvasItems in Python, use the classes' "create" methods
instead of the constructors.  This prevents Python from trying to
destroy them.

Added the bool argument to PythonExportableBase<>::pythonObject()
controlling ownership of the exported object.

Added Canvas::datadump, which writes the contents of the canvas to a
text file, for debugging.

Restrict pdf output to pdf version 1.4, for reproducibility in tests,
theoretically.  Pdf generation appears to not be portable.

Added support for scikit-image/numpy images.  Set OOFCANVAS_USE_NUMPY
in cmake to enable it.

1.0.2

Fixed build problems that showed up in OOF2 when using MacPorts, and
could theoretically occur here too.

1.0.1

Added Rectangle constructor in python.

Added oofcanvasgui.h to the user-visible header files.

Added this changelog.

1.0.0

Initial pre-release, e-mailed to a small number of users.
