Kodi Arfer 1732ddec4d Disable the parser cache
I wasn't able to observe a meaningful performance improvement from it, and it requires some file I/O. Here are the times, in seconds, I observed on my ThinkPad T450s with Python 3.6 and Ubuntu 18.04:

                test 1  test 2
    master       8.96    2.59
    this change  8.88    2.62

Test 1 is the total time from:

$ time dash -c 'git clean -dfx && pip install -e . && pytest --ignore tests/test_bin.py'

Test 2 is pytest's reported total time from a subsequent:

$ pytest --ignore tests/test_bin.py
2018-05-21 09:22:49 -07:00
..
2018-04-29 19:51:00 -07:00
2018-05-21 09:22:49 -07:00
2018-04-12 16:45:17 -07:00
2018-01-01 10:38:33 -05:00
2018-03-24 12:34:43 -07:00