Added new parameter 'encrypt' with same semantics from that of
vars_prompt. When encryption is requested a random salt will be
generated and stored along the password in the form:
'<password> salt=<salt>'.
Also store passwords with an ending '\n' for easier looking at files
with console tools. File content was being already rstripped so this
is harmless.
Alan Fairless
Maykel Moya
Michael DeHaan
Javier Candeira