add timeout to TabCAT.Couch.login() and TabCAT.Couch.logout()
add timeout to TabCAT.User.login() and TabCAT.User.logout()
add 4-second timeout for login/logout
show 'Logging in...' when logging in.
show "Logging out..." when user clicks logout button
don't overwrite username if user decides not to log out
Merge pull request #161 from davidmarin/login-timeout

Timeout for login/logout