requirements and examples folder should not be packaged.

[ethanluoyc]

Hi, given the current setup.py, the requirements and example folder are packaged in the wheel. I don't think this is intended and this has caused some issues for downstream usage. I created a PR with a fix, could you kindly take a look at #132 ?

[garymm]

This appears to make this package unusable with Bazel (or maybe only in combination with another package that also includes an examples module).