Add check for NickServ password notification message

- Move channel joining code into $scope.joinChannels
Refactor/restructure login.js:

- Take Connection event handlers out of $scope functions
- Add setError function that takes care of $rootScope.$apply
- Get rid of `connecting` and `connected` variables in LoginCtrl and instead put them in the Connection API
Move event registration to a separate function
Remove obsolete code
Merge pull request #76 from coldstorm/rework-login-process

Rework login code