Added build wrapper so build_ext runs before build_py

[daviesrob]

SWIG, run by build_ext, generates a shared object file and a python library. The latter needs to be generated before build_py is run so that build_py finds it. Unfortunately the default in setuptools is to run build_py before build_ext. The solution is to override the build class so that the build order can be changed.

With this change, "pip install" works better, including when lsf-python-api is a dependency of another module.

See: https://bugs.python.org/issue2624 https://bugs.python.org/issue1016626 https://stackoverflow.com/questions/12491328/python-distutils-not-include-the-swig-generated-module https://stackoverflow.com/questions/50239473/building-a-module-with-setuptools-and-swig

Signed-off-by: Robert Davies [email protected]