decision: remove old vle::value::init call

The vle::value::init function disappear in VLE 1.1. We replace all call
with the vle::Init object.
cellqss: assign default path for scripts

Assign a default path for the VleCheckPackage.cmake script since CMake
complains to not found this script.
examples: assign default path for scripts

Assign a default path for the VleCheckPackage.cmake script since CMake
complains to not found this script.
celldevs: install missing header

The header files of the extension was missing in install part of the
CMakeLists.txt.
de: install missing header

The header files of the extension was missing in install part of the
CMakeLists.txt
fsa: install missing header

The header files of the extension was missing in install part of the
CMakeLists.txt.
petrinet: install missing header

The header files of the extension was missing in install part of the
CMakeLists.
decision: install missing header

The header files of the extension was missing in install part of the
CMakeLists.txt.
differential: install missing header

The header files of the extension was missing in install part of the
CMakeLists.