add a catch_all plugin function to see all messages from slack
add a catch_all plugin function to see all messages from slack

jayeshc1990/slackbot,cworth-gh/stony,FundingGates/python-rtmbot,farshield/bountybot,errror/python-rtmbot,changlingbob/r2d6,askdjango/python-rtmbot,slackhq/python-rtmbot,petersen-poul/python-rtmbot,hacklag/hackbot,adamfazzari/python-rtmbot,kenden/python-rtmbot,erynofwales/ubot2,dwfchu/python-rtmbot,Zyzle/python-rtmbot,RyanGladstone/python-rtmbot,hlprimm/python-rtmbot,PythonSanSebastian/python-rtmbot,ChihChengLiang/python-rtmbot,erynofwales/ubot2,pyamanak/oithdbot,mtermoul/starbot,hacklag/hackbot,mathias-baumann-sociomantic/dante,henryfjordan/incident-commander,aerickson/python-rtmbot,eegeo/python-rtmbot,sqlbyme/python-rtmbot,SovcikJoe/python-rtmbot,jammons/python-rtmbot,BAM-X/python-rtmbot,0xrofi/python-rtmbot,errror/python-rtmbot,youknowone/slairck