isa, a tool for Integer Set Analysis

Some common commands:

- extract a polyhedral model from test.c

	c2pdg test.c

  The polyhedral model is stored in test.yaml

- perform dataflow analysis

	da -i test.yaml

  The results are stored in test_da.yaml

- print dependences

	dump_dependences < test_da.yaml

- convert to a process network

	pn < test.yaml > test_pn.yaml

- write out C code again for a (possibly transformed) polyhedral model

	pdg2c test.c test_pn.yaml