Cleanup and speedup of test/test_turbo_seti.py

[texadactyl]

It was due for some overhaul.

• The validate_voyager_hits function was not showing information when it failed.
• DAT, LOG, and PNG files were being created outside of the test subdirectory.
• Some speedup was gained by lowering the max_drift parameter value from 4 and 10 down to 2 in every individual test.

While I was at it, I also lowered the max_drift rate in test/test_pipelines_1.py too.