Retain Full Subfolder Structure In Packages

[sommersoft]

As highlighted in a recent release attempt for Adafruit_CircuitPython_ImageLoad, sub-subfolders were dropping their immediate parent folder.

I did a regression test on an older full Bundle (~10 days old), and everything looks good.

Test result on the updated ImageLoad library, shows that subfolder structure is now retained:

~/Dev/cpy-build-tools:$> unzip -l test-2.x-mpy-930c053.zip
Archive:  test-2.x-mpy-930c053.zip
{"build-tools-version": "1.1.6.dev44+g67abd08"}
  Length      Date    Time    Name
---------  ---------- -----   ----
      600  2019-05-31 18:46   test-2.x-mpy-930c053/lib/adafruit_imageload/__init__.mpy
      713  2019-05-31 18:46   test-2.x-mpy-930c053/lib/adafruit_imageload/pnm/pbm_binary.mpy
      679  2019-05-31 18:46   test-2.x-mpy-930c053/lib/adafruit_imageload/pnm/ppm_binary.mpy
     1242  2019-05-31 18:46   test-2.x-mpy-930c053/lib/adafruit_imageload/pnm/__init__.mpy
      990  2019-05-31 18:46   test-2.x-mpy-930c053/lib/adafruit_imageload/pnm/ppm_ascii.mpy
      425  2019-05-31 18:46   test-2.x-mpy-930c053/lib/adafruit_imageload/pnm/pbm_ascii.mpy
      653  2019-05-31 18:46   test-2.x-mpy-930c053/lib/adafruit_imageload/pnm/pgm/binary.mpy
      522  2019-05-31 18:46   test-2.x-mpy-930c053/lib/adafruit_imageload/pnm/pgm/__init__.mpy
      934  2019-05-31 18:46   test-2.x-mpy-930c053/lib/adafruit_imageload/pnm/pgm/ascii.mpy
      771  2019-05-31 18:46   test-2.x-mpy-930c053/lib/adafruit_imageload/bmp/__init__.mpy
      687  2019-05-31 18:46   test-2.x-mpy-930c053/lib/adafruit_imageload/bmp/indexed.mpy
      457  2019-05-31 18:46   test-2.x-mpy-930c053/examples/imageload_colorwheel.py
     1232  2019-05-31 18:46   test-2.x-mpy-930c053/examples/imageload_netpbm.py
      244  2019-05-31 18:46   test-2.x-mpy-930c053/examples/imageload_simpletest.py
---------                     -------
    10149                     14 files

[tannewt]

Great! Thank you!