Add command "leave" (very well-known to ircII users) as an alias for "part".
Add timestamps to all messages, using the basic locale format.

Resolves issue #133.
Merge pull request #181 from tvierling/timestamping

Add timestamps to all messages, using the basic locale format.
Merge pull request #182 from tvierling/leave_command

Add command "leave" (very well-known to ircII users) as an alias for "part".