Script updates - who is and who is user methods

The changes involve:
1. robot will respond to 'hubot who is <role>' instead of  'who is <role>' 
2. robot will respond to 'hubot who is user <user>' instead of 'hubot who is <user>'. I did this because right now we often mistake two functions: 'how can I list all users with role' and 'how can I see the roles assigned to a user'
3. the user will not be able to kill hubot - temporary patch