fixes #2: Add a decoder for morse code

[slaterslater]

Added argparse to handle command line arguments:

• -w or --wav to create a wav file
• -r or --read to read a wav file
• -p or --play to play a wav file

Added new functions:

• encoder_to_wav() writes string of dots & dashes as a wav file
• wav_to_encoder() converts wav file into string of dots & dashes
• decoder() translates string of dots & dashes as text

[nimit2801]

hey @slaterslater can you add the how to use decoder in comments or readme.md so that people can you it in the correct manner? :) And btw great work! 👍

[slaterslater]

Ok I’ll send another PR shortly. And thanks!