Looping, punctuation and translator

1. Added looping through the alphabet dictionary as a first step (to
create lists of alphanumeric characters and Morse code).

2. Added punctuation mark capability (except the period character, which
is 'e' in Morse).

3. Created a Morse to English translator.

There are some other, smaller changes to the functions, but I've added
comments in the code to highlight those.