misnamed folder using pip install

Hi

FYI Pip installation goes fine on my Ubuntu OS, but import pyprosail gives an error. The issue is about case in folder's name.
- _prosail_model.so is in "PyPROSAIL" folder
- python scripts are in "pyprosail" folder
  After moving the _prosail_model.so file, import pyprosail works.

Regards,
