Remove shebang from all files except ticket.py since they are not meant to be
executed.  Also remove UTF-8 vim coding since all files are ASCII only.
Remove unused import `replay'.
Use class alias for readability.
Refactor comments.
Only declare variable if we are the server.
No longer check if `uniformDHSecret' exists because it is now mandatory.
Remove the ability to manually specify a ticket file since this should be
handled transparently.  Only a way to specify the UniformDH shared secret is
exposed to the user.
Refactor comment.
Refactor comments and add an assert to `_deriveSecrets()'.