Make hybrid-editable installs work with nox

[dhermes]

Goal would be to install editable (pip install -e .) but then have a hook in nox.py which would check if any of the files with a particular extension have changed and then re-build if that was the case.

Relevant extensions (as of 3dfc56d):

• .c
• .f
• .f90
• .h
• .pxd
• .pyx

Also relevant:

• nox.py
• setup.cfg
• setup_helpers.py
• setup_helpers_osx.py
• setup_helpers_windows.py
• setup.py

[dhermes]

In total this is 27 source files:

$ git ls-files '*.c' '*.f' '*.f90' '*.h' '*.pxd' '*.pyx'
src/bezier/_curve.pxd
src/bezier/_curve_intersection.pxd
src/bezier/_curve_intersection_speedup.c
src/bezier/_curve_intersection_speedup.pyx
src/bezier/_curve_speedup.c
src/bezier/_curve_speedup.pyx
src/bezier/_helpers.pxd
src/bezier/_helpers_speedup.c
src/bezier/_helpers_speedup.pyx
src/bezier/_surface.pxd
src/bezier/_surface_speedup.c
src/bezier/_surface_speedup.pyx
src/bezier/curve.f90
src/bezier/curve_intersection.f90
src/bezier/helpers.f90
src/bezier/include/bezier.h
src/bezier/include/bezier/curve.h
src/bezier/include/bezier/curve_intersection.h
src/bezier/include/bezier/helpers.h
src/bezier/include/bezier/surface.h
src/bezier/quadpack/d1mach.f
src/bezier/quadpack/dqagse.f
src/bezier/quadpack/dqelg.f
src/bezier/quadpack/dqk21.f
src/bezier/quadpack/dqpsrt.f
src/bezier/surface.f90
src/bezier/types.f90

and 5 "config" files.

[dhermes]

This is done (in a somewhat different fashion than originally described) as of #176. The primary slow-down has been resolved by cmake caching the built libbezier.