fix imports in integration test so we don't run tests twice
remove "if __name__ == __main__ blocks from test code
clean up/refactor main_test.py
make graph.subninjas, graph.includes lists; add tests to get full coverage of analyzer
add main.TestBuild.test_subdirs(), lots of code cleanup
add main_test.TestBuild.test_command_fails, test_input_file_in_subdir, other placeholder tests yet to be written
add more placeholders in main_test.py (test_ctrl_c, test_no_work_to_do)
add more tests for printer.py
add tests for stats, fixes for stats