Deal with modules management differently

It is a crappy implementation, i know

The idea is that people might want a custom modules configuration and so if LISTING exists then secilc will just try to use it
This allows one to add modules to the list and remove from the list manually

If LISTING does not exist then splash.sh generates one that includes all .cil suffixed files except the ones in "EXCLUDE" layers (currently the testing layer only)

Furthermore, splash.sh accepts all options that secilc accepts. Thus for example: "./splash.sh -D" would build policy without dontaudit rules
Fragile but it provides a single place to:
    define set of absolute minimal requirements
    defile a set of minimal requirements
    run all tests from