make PASS command work for authentication

The previous work on this (https://github.com/flowdock/oulu/pull/31) didn't result in a working implementation. The attached code works for me when testing with LimeChat (a fairly generic IRC client for OS X) and follows the RFC for IRC on the PASS command (http://www.irchelp.org/irchelp/rfc/chapter4.html#c4_1_1). The command sequence the client issued was:

03:05:39 app.1     | PASS *********
03:05:39 app.1     | NICK a
03:05:39 app.1     | USER user@*****.com 0 * c

The comments in pull request 31 seem to be attempting to auth on /connect (which seems pretty different).

Comments about the changes:

pass_command.rb:
  - email should be ignored by this command. the RFC specifies 'PASS pass', with no email.

user_command.rb
  - email should be taken directly from the user input