Files in testing examples not found under windows

Since file paths in Windows and Unix systems are expressed differently, the current implementation in the testing files causes issues in Windows. Fixing this might make the code more readable and show good practice for less experienced users.

Current implementation (example from test_calib.py line 197ff):

coord_calib_csv_path = os.path.join(os.getcwd(),

                                        'data/mosquito_escapes/calib/xyz_calibration_device.csv')

    pts_calib_csv_path = os.path.join(os.getcwd(),

                                      'data/mosquito_escapes/calib/20200306_xypts.csv')

Idea for a solution:

coord_calib_csv_path = os.path.join(os.getcwd(),

                                        'data','mosquito_escapes','calib','xyz_calibration_device.csv')

pts_calib_csv_path = os.path.join(os.getcwd(),

                                      'data','mosquito_escapes','calib','20200306_xypts.csv')

os.path.join then generates the correct paths.