Parse default parameters

[AlexDo1]

Just as for the json2args and json2aRgs packages, the function getParameters.m must be extended to parse default parameters correctly according to the tool specification.

This issue also exists in the tool_template_octave repository: tool-spec/tool_template_octave#2
As the getParameters() function is the same for Matlab and in Octave, getParameters() has to be extended only once and can then be copied over.