wordlist audit mode

[raspberryaether]

Implement an "audit" mode to provide the ability to swap out undesirable (vulgar and/or hard to remember or spell) words.

A suggested mode of implementation:

1. The word is printed, upon which the user is prompted "(K)eep? (D)iscard? (B)ack? ".
   a. Keep will result in the current word being added to the revised wordlist and the next word being shown.
   b. Discard will show the next word. The current word will not be added.
   c. Back will remove the previous word added to the revised wordlist and present it again for decision.
2. The user is prompted for a filename in which to save the revised wordlist.

Acceptance Criteria:

• A wordlist audit mode such as the one described above is implemented.
• A mechanism is present to use the customized wordlists.
• The readme is updated with an explanation of the new mode.