Fix IRC link in README. Closes gh-951.
Fix IRC link in README. Closes gh-951.

Chhunlong/grunt,arosa81/grunt,fscherwi/grunt,IveWong/grunt,modulexcite/grunt,coldrye-collaboration/grunt,zackexplosion/grunt,vladikoff/grunt,yuhualingfeng/grunt,FeodorFitsner/grunt,goodeggs/grunt,paulcbetts/grunt,imjerrybao/grunt,thecc4re/gruntjs,eelve/grunt,thejameskyle/grunt,yosiazwan/grunt,paladox/grunt,r14r-work/fork_grunt_master,ThiagoGarciaAlves/grunt,lkiarest/grunt,youmyyou/grunt,q310550690/grunt,abraheem/grunt,shama/grunt,pandeysoni/grunt,r14r/fork_grunt_master,JaKXz/grunt,yonglehou/grunt,felixgrey/grunt