Fix Python bindings for heat map generation

[marip8]

reach/src/python/python_bindings.cpp

Lines 298 to 299 in 5a3e4ca

	bp::def("computeHeatMapColors", &computeHeatMapColorsPython1);
	bp::def("computeHeatMapColors", &computeHeatMapColorsPython2);

The default values for the heat map generator functions are not being populated into the Python API. We need to add additional arguments to bp::def to define the default values. See this post for a reference solution

[marip8]

Closing; addressed in #68