Add dropout_input_mask_value support.
Add dropout_input_mask_value support.

CIFASIS/pylearn2,chrish42/pylearn,Refefer/pylearn2,skearnes/pylearn2,fishcorn/pylearn2,fulmicoton/pylearn2,hantek/pylearn2,jamessergeant/pylearn2,aalmah/pylearn2,pkainz/pylearn2,pombredanne/pylearn2,jeremyfix/pylearn2,ashhher3/pylearn2,cosmoharrigan/pylearn2,abergeron/pylearn2,w1kke/pylearn2,bartvm/pylearn2,ddboline/pylearn2,theoryno3/pylearn2,mkraemer67/pylearn2,lancezlin/pylearn2,mkraemer67/pylearn2,lunyang/pylearn2,CIFASIS/pylearn2,nouiz/pylearn2,hyqneuron/pylearn2-maxsom,daemonmaker/pylearn2,woozzu/pylearn2,sandeepkbhat/pylearn2,fyffyt/pylearn2,lunyang/pylearn2,ashhher3/pylearn2,hantek/pylearn2,nouiz/pylearn2,msingh172/pylearn2,w1kke/pylearn2,ddboline/pylearn2,alexjc/pylearn2,cosmoharrigan/pylearn2,jeremyfix/pylearn2,JesseLivezey/pylearn2,lisa-lab/pylearn2,aalmah/pylearn2,theoryno3/pylearn2,abergeron/pylearn2,JesseLivezey/plankton,matrogers/pylearn2,ddboline/pylearn2,daemonmaker/pylearn2,CIFASIS/pylearn2,pombredanne/pylearn2,aalmah/pylearn2,caidongyun/pylearn2,shiquanwang/pylearn2,matrogers/pylearn2,chrish42/pylearn,goodfeli/pylearn2,KennethPierce/pylearnk,hyqneuron/pylearn2-maxsom,TNick/pylearn2,kose-y/pylearn2,fulmicoton/pylearn2,jeremyfix/pylearn2,JesseLivezey/pylearn2,woozzu/pylearn2,alexjc/pylearn2,lamblin/pylearn2,jamessergeant/pylearn2,lamblin/pylearn2,fishcorn/pylearn2,jamessergeant/pylearn2,se4u/pylearn2,fyffyt/pylearn2,skearnes/pylearn2,bartvm/pylearn2,msingh172/pylearn2,matrogers/pylearn2,junbochen/pylearn2,caidongyun/pylearn2,KennethPierce/pylearnk,TNick/pylearn2,ashhher3/pylearn2,junbochen/pylearn2,mkraemer67/pylearn2,daemonmaker/pylearn2,msingh172/pylearn2,ashhher3/pylearn2,hyqneuron/pylearn2-maxsom,fyffyt/pylearn2,pombredanne/pylearn2,msingh172/pylearn2,caidongyun/pylearn2,kastnerkyle/pylearn2,ddboline/pylearn2,JesseLivezey/pylearn2,pombredanne/pylearn2,mkraemer67/pylearn2,kastnerkyle/pylearn2,daemonmaker/pylearn2,lunyang/pylearn2,jamessergeant/pylearn2,cosmoharrigan/pylearn2,fishcorn/pylearn2,abergeron/pylearn2,kastnerkyle/pylearn2,sandeepkbhat/pylearn2,JesseLivezey/plankton,JesseLivezey/pylearn2,caidongyun/pylearn2,woozzu/pylearn2,lamblin/pylearn2,pkainz/pylearn2,mclaughlin6464/pylearn2,shiquanwang/pylearn2,nouiz/pylearn2,lunyang/pylearn2,skearnes/pylearn2,shiquanwang/pylearn2,lancezlin/pylearn2,fulmicoton/pylearn2,skearnes/pylearn2,chrish42/pylearn,abergeron/pylearn2,se4u/pylearn2,jeremyfix/pylearn2,KennethPierce/pylearnk,sandeepkbhat/pylearn2,kastnerkyle/pylearn2,kose-y/pylearn2,lisa-lab/pylearn2,hantek/pylearn2,goodfeli/pylearn2,mclaughlin6464/pylearn2,mclaughlin6464/pylearn2,aalmah/pylearn2,cosmoharrigan/pylearn2,JesseLivezey/plankton,lisa-lab/pylearn2,Refefer/pylearn2,bartvm/pylearn2,lancezlin/pylearn2,chrish42/pylearn,goodfeli/pylearn2,matrogers/pylearn2,kose-y/pylearn2,alexjc/pylearn2,pkainz/pylearn2,lisa-lab/pylearn2,se4u/pylearn2,KennethPierce/pylearnk,se4u/pylearn2,fulmicoton/pylearn2,w1kke/pylearn2,TNick/pylearn2,fyffyt/pylearn2,hantek/pylearn2,CIFASIS/pylearn2,lancezlin/pylearn2,theoryno3/pylearn2,pkainz/pylearn2,bartvm/pylearn2,lamblin/pylearn2,Refefer/pylearn2,TNick/pylearn2,junbochen/pylearn2,theoryno3/pylearn2,JesseLivezey/plankton,mclaughlin6464/pylearn2,junbochen/pylearn2,shiquanwang/pylearn2,Refefer/pylearn2,goodfeli/pylearn2,hyqneuron/pylearn2-maxsom,sandeepkbhat/pylearn2,alexjc/pylearn2,nouiz/pylearn2,fishcorn/pylearn2,w1kke/pylearn2,kose-y/pylearn2,woozzu/pylearn2