moved the code to calculate basic information.

added a test referred to the semtech calculator..

added example of the command line.

enabled to show raw data rate.

moved argument parser into lorawan_toa_cal.py

supported python3

removed the output of japan regulation.

fixed an example. the output was taken from other output...

enable to show data rate in Japan regulation.

moved parse_args() from library to toa.py.

changed the place of note.

fixed the old text.

added a note.

updated the usage.

- added toa.py for python3. get_toa() moved into lorawan_toa_cal.py.