Added note field to credentials table.
Added note parameter to safeword_credential_create().
Implemented committing note to database in safeword_credential_add().
The show command now prints note if exists.
Refactored add command to parse note from stdin, a file, or string.
Added support to safeword_credential_update for note field.
Updated edit command to support editing note field.
Added safeword-edit asciidoc. Updated safeword-add asciidoc with note parameter.