move sessions to a separate directory

Citadelle/ROOT

...ples/Employee_Model/Analysis_generation/Analysis_deep.thy

...s/Employee_Model/Analysis_generation/Analysis_shallow.thy

...examples/Employee_Model/Design_generation/Design_deep.thy

...mples/Employee_Model/Design_generation/Design_shallow.thy

Citadelle/examples/archive/compiler/Monads.thy

Citadelle/examples/archive/uml_ocl/Flight_Model_compact.thy

Citadelle/examples/archive/uml_ocl/Isabelle_Finite_Set.thy

Citadelle/examples/archive/uml_ocl/OCL_core_experiments.thy

...le/examples/archive/uml_ocl/OCL_lib_Gogolla_challenge.thy

...les/archive/uml_ocl/OCL_lib_Gogolla_challenge_integer.thy

...mples/archive/uml_ocl/OCL_lib_Gogolla_challenge_naive.thy

Citadelle/examples/archive/uml_ocl/Simple_Model.thy

Citadelle/examples/archive/uml_ocl/Toy_deep.thy

Citadelle/examples/archive/uml_ocl/Toy_shallow.thy

Citadelle/examples/uml_ocl/AbstractList.thy

Citadelle/examples/uml_ocl/Bank_Model.thy

Citadelle/examples/uml_ocl/Bank_Test_Model.thy

Citadelle/examples/uml_ocl/Clocks_Lib_Model.thy

Citadelle/examples/uml_ocl/Flight_Model.thy