Configurable symbol list and put digits into a separate category.

[alanhoyle]

Two related issues here:

1. Some password systems consider digits and symbols to be a separate category and require at least one character from each.
2. Some password systems require that your symbols come from their defined list of symbols.

Quoting my work's password rules (in part):

• It must contain at least one digit
• It must contain at least one of these characters: !@#$%&*+={}?<>"'

[madduck]

I would also really appreciate that -s ("symbols") generated symbols, and maybe -u was introduced to select a certain number of numbers (given how -n is already taken).

[madduck]

Any news on this, @ulif? Is this something to pursue, and are you waiting for a pull request?