Clean repo for releases

[noahzemlin]

Currently, the zip file attached in the releases is a raw zip of the repository. This leads to a lot of unnecessary and potentially harmful files that user do not need like catchlib/, travis configs, and unit tests. There should be a script to clean the folder of these unnecessary files to zip for release.

Ideally, this should be written in either Python or Bash so that it can be integrated into CI easily.

[noahzemlin]

With RobotLib to be soon added to the Arduino Library manager, this is much less important since the Arduino IDE just clones the repo when it imports libraries. This issue is still useful though for the case where somebody wants a very light version of this library. The full size of this repo is in the magnitude of 100 Kilobytes while it can be reduced down to the magnitude of 1 Kilobyte.