Robotics Systems Types

Instead of putting the rst sandbox include directories into the RSTSANDBOX_INCLUDE_DIRS cmake variable, these directories are appended at the RST_INCLUDE_DIRS if the the sandbox is used. Although this - technically - should not result in any erros or misconfiguration of cmake when following the instructions in http://docs.cor-lab.de/rst-manual/0.7/html/tutorial.html#tutorial, it might cause some confusion for users debugging their cmake configuration who are facing an empty RSTSANDBOX_INCLUDE_DIRS variable...