main(argc, argv) --> int main(int argc, char** argv)
Although we accept int, void, and char types, and pointers to same,
we actually still treat everything as an int.
Document internal CodeGenerator interface
Move license to a separate license file.
Define a public API for calling libacc.
Update the "acc" test program to use the public API.
Move "main.cpp" and test scripts into the tests subdirectory.
Move test data from tests to tests/data
Remove stale test data.
