"develop" installation broken

[wcpettus]

Attempting to pip install editable (/develop) yields broken executables. For dl-serve::

Traceback (most recent call last):
  File "/usr/local/bin/dl-serve", line 10, in <module>
    import dripline
  File "/usr/local/src_py/dripline/__init__.py", line 1, in <module>
    from . import core
  File "/usr/local/src_py/dripline/core/__init__.py", line 4, in <module>
    from _dripline.core import *
ModuleNotFoundError: No module named '_dripline.core'

Reproducible by changing this line to RUN pip install -v -e /usr/local/src_py in Dockerfile:
https://github.com/driplineorg/dripline-python/blob/develop/Dockerfile#L26

Develop installation of the code is very useful for rapidly developing and testing modifications to the dl-py code. Would be great to get this feature fixed - probably it's an issue coming from the pybind11.