update KNOWN_ISSUES with some more things I thought of.
update KNOWN_ISSUES with some more things I thought of.

like the obvious bug with global imports in fabfiles, and something like Capistrano roles.

fernandezcuesta/fabric,opavader/fabric,hrubi/fabric,elijah513/fabric,MjAbuz/fabric,pashinin/fabric,cgvarela/fabric,tekapo/fabric,xLegoz/fabric,itoed/fabric,ploxiln/fabric,askulkarni2/fabric,likesxuqiang/fabric,cmattoon/fabric,haridsv/fabric,sdelements/fabric,getsentry/fabric,bitmonk/fabric,mathiasertl/fabric,rbramwell/fabric,simon-engledew/fabric,rane-hs/fabric-py3,kxxoling/fabric,bitprophet/fabric,bspink/fabric,jaraco/fabric,amaniak/fabric,tolbkni/fabric,TarasRudnyk/fabric,ericholscher/fabric,kmonsoor/fabric,SamuelMarks/fabric,StackStorm/fabric,raimon49/fabric,rodrigc/fabric,felix-d/fabric,akaariai/fabric,pgroudas/fabric,qinrong/fabric