SP: simplify active columns assignment
SP: simplify active columns assignment

is now a list, instead of ndarray

sambitgaan/nupic,blueburningcoder/nupic,rcrowder/nupic,pap/nupic,wanghaven/nupic,vitaly-krugl/nupic,ywcui1990/nupic,pulinagrawal/nupic,scottpurdy/nupic,wanghaven/nupic,neuroidss/nupic,rhyolight/nupic,runt18/nupic,marionleborgne/nupic,sambitgaan/nupic,fergalbyrne/nupic,sambitgaan/nupic,EricSB/nupic,ywcui1990/nupic,jcasner/nupic,numenta/nupic,lscheinkman/nupic,go-bears/nupic,numenta/nupic,blueburningcoder/nupic,vitaly-krugl/nupic,subutai/nupic,arhik/nupic,runt18/nupic,badlogicmanpreet/nupic,SaganBolliger/nupic,pap/nupic,cogmission/nupic,SaganBolliger/nupic,rhyolight/nupic,arhik/nupic,breznak/nupic,runt18/nupic,subutai/nupic,cogmission/nupic,pulinagrawal/nupic,cogmission/nupic,markneville/nupic,rhyolight/nupic,alfonsokim/nupic,scottpurdy/nupic,badlogicmanpreet/nupic,numenta-ci/nupic,vitaly-krugl/nupic,fergalbyrne/nupic,jcasner/nupic,lscheinkman/nupic,passiweinberger/nupic,ywcui1990/nupic,neuroidss/nupic,wanghaven/nupic,markneville/nupic,markneville/nupic,neuroidss/nupic,SaganBolliger/nupic,subutai/nupic,scottpurdy/nupic,passiweinberger/nupic,alfonsokim/nupic,rcrowder/nupic,pulinagrawal/nupic,badlogicmanpreet/nupic,BoltzmannBrain/nupic,breznak/nupic,go-bears/nupic,blueburningcoder/nupic,BoltzmannBrain/nupic,pap/nupic,jcasner/nupic,BoltzmannBrain/nupic,rcrowder/nupic,passiweinberger/nupic,EricSB/nupic,lscheinkman/nupic,arhik/nupic,marionleborgne/nupic,fergalbyrne/nupic,numenta-ci/nupic,alfonsokim/nupic,breznak/nupic,numenta-ci/nupic,EricSB/nupic,numenta/nupic,go-bears/nupic,marionleborgne/nupic