Fix softmax overflow
Fix softmax overflow

rcrowder/nupic,subutai/nupic,alfonsokim/nupic,neuroidss/nupic,neuroidss/nupic,numenta/nupic,subutai/nupic,alfonsokim/nupic,neuroidss/nupic,rhyolight/nupic,alfonsokim/nupic,numenta/nupic,rcrowder/nupic,subutai/nupic,rcrowder/nupic,numenta/nupic,rhyolight/nupic,rhyolight/nupic