Building binaries (wheels) for linux

Hey hey,

Thanks for this project, this is great stuff!

Have you considered integrating a building step into your travis or gitlab-ci pipeline that would generate Linux binaries (wheels) and push them to PyPI? Something along these lines:

https://github.com/gmagno/pyopencl/blob/master/travis/build-wheels.sh
https://github.com/gmagno/pyopencl/blob/master/.travis.yml

Travis build: https://travis-ci.com/gmagno/pyopencl/builds/98730557

The above repo is currently generating the following builds on a Centos5 which I haven't tested on any other distro besides Ubuntu16.04, but it should work™ on "manylinux"-es:

https://pypi.org/project/pyopencl-gm/#files

This would be important for obvious reasons: not having to build pyopencl and install dependencies (numpy, pybind11 and mako) beforehand, so atm:

pip install pyopencl-gm
python -c "import pyopencl as cl; print(cl.get_platforms())"

just works.

This follows `pypa/manylinux` (PEP513). They provide an example here: https://github.com/pypa/python-manylinux-demo.

I am fairly new with pyopencl, so I am not 100% confident about the impact on your project.