DifferenceEquation: gvle plugin for windows bug

[rtrepos]

Using the gvle plugin of DifferenceEquation, we have a Seg fault when trying to add a second parameter. It occurs only on windows. Steps to reproduce:

• open a new project, open the empty.vpz file
• add an atomic model, generate a new dynamic for this model based on DifferenceEquationMultiple
• add a parameter
• add a new parameter

A gdb trace shows this line:

 #23 0x060cdddb in vle::gvle::modeling::de::Parameters::ParametersTreeView::onAdd (this=0x5d19c08)
      at C:\Users\rtrepos\AppData\Local\Temp\vle.extension.difference-equation\src\vle\gvle\modeling\difference-equation\Parameters.cpp:176

[rtrepos]

This bugs occured on vle-1.1.1 Nevertheless, it does not occur with vle-1.1.2 using the distribution version of vle packages.