Improve setup script

Scripts/setup.sh

 DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
-export PYTHONPATH=${PYTHONPATH}:${DIR}/../Python
-export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:${DIR}/../Pcie40Libraries/lib:${DIR}/../Pcie40DriverLibraries
-export PATH=${PATH}:${DIR}/../Pcie40Applications
+export PYTHONPATH=${DIR}/../Python:${PYTHONPATH}
+export LD_LIBRARY_PATH=${DIR}/../Pcie40Libraries/lib:${DIR}/../Pcie40DriverLibraries:${LD_LIBRARY_PATH}
+export PATH=${DIR}/../Pcie40Applications:${PATH}
 export PCIE40_DRIVER_DIR=${DIR}/../Pcie40Driver