Handle nested inclusions in mtc scripts, and require proper structure

Now the main.mtc file (or whatever its name) needs to put in the same place it would be in a real simulation case ; in the older example case, main.mtc was moved into the Scripts folder and starting 'cimlib_driver main.mtc' from there didn't work since the driver wants the paths to be correct from the folder where main.mtc resides. This change needed to handle paths very explicitely from the start of the script, and to do so, dirname and basename have been added as dependencies.