Added TOPAS binary exporter

[icmeyer]

Have been finding this module very useful. I added a TOPAS binary exporter using the numpy.ndarray.tofile() function. This is in line with the reverse operation of the topas2numpy's import using numpy.fromfile().

The one drawback of the binary format is that it can't be transferred across systems of different endianness. I believe this is baked into the format for all TOPAS users, so maybe we add a warning along these lines when exporting to binary?

Added a test to the testsuite, and tested the binary import with OpenTOPAS v4.0.0

[bwheelz36]

Thanks for this, this is a functionality I have been wanting to add for a while!

• for the file endings, you could correct rather than warn: https://stackoverflow.com/questions/58363093/how-to-convert-dos2unix-csv-file-with-python-script. I think the warnings are fine though, happy to accept as is. I guess the main use case where this would be an issue is working on windows with topas in a docker container.

[icmeyer]

Fixed up the docstring and added in a warning about the binary format