improved pattern matching

- improved regular expression matching
- now supports "what role(s) do I have" query
fix erroneous response when only one admin exists (the user)

Previously Hubot would respond "no admins" when the only admin
was the user querying who has admin roles
capitalize OK
add 'who has X role' command

Reports all users who have the given role
update commands list
updated README.md and contributors
add userRoles method
use userRoles method for 'what roles' response
consolidate 'who has X role' responses
fix invalid reference in usersWithRole method
update hasRole method to call userRoles for better role matching
update 'who has' response to call usersWithRole
add missing assignment
remove redundant code
push correct value (name)
fix invalid method call
Merge pull request #6 from therealklanni/master

Adds command to list users with role. Cleans up regex.