Fix PIRC README
completed by: Nagato Yuki
mentors: whiteknight
Task Description: Ticket #1913 suggests several improvements to PIRC's README file. This file is important because it is the first and often the only bit of documentation a user will read before attempting to use PIRC. Proof-read the README file and account for the issues described in this ticket, in addition to any other improvements you feel are worth making