Add .gitignore.
Change add_test.py to output the concatenated raw/report to stdout.

Instead of appending it to test_stash.
Rename: add_test.py -> create_test.py
Refactor the tests: put each test case in a separate file

Instead of one big pile of tests in tests_stash.txt, keep each CPU
example raw data/parsed data in a file, ordered in a tree by
manufacturer and microarchitecture. The 64 .test files have been
extracted from tests_stash.txt. The add_test script is changed to
create_test and it doesn't append to test_stash.txt, instead it
spits out data to be saved in a .test file.

run_tests.py is not refactored yet, to be done in a subsequent commit.