made GP_regression wwork with partial-passed gradients
made GP_regression wwork with partial-passed gradients

ysekky/GPy,Dapid/GPy,esiivola/GPYgradients,fivejjs/GPy,dhhjx880713/GPy,AlexGrig/GPy,SheffieldML/GPy,befelix/GPy,AlexGrig/GPy,TianpeiLuke/GPy,avehtari/GPy,mikecroucher/GPy,mikecroucher/GPy,buntyke/GPy,esiivola/GPYgradients,ptonner/GPy,SheffieldML/GPy,mikecroucher/GPy,PredictiveScienceLab/GPy,befelix/GPy,Dapid/GPy,mikecroucher/GPy,AlexGrig/GPy,jameshensman/GPy,strongh/GPy,TianpeiLuke/GPy,maaskola/GPy,esiivola/GPYgradients,fivejjs/GPy,dhhjx880713/GPy,befelix/GPy,ysekky/GPy,fivejjs/GPy,ysekky/GPy,maaskola/GPy,AlexGrig/GPy,buntyke/GPy,jameshensman/GPy,beckdaniel/GPy,jameshensman/GPy,avehtari/GPy,dhhjx880713/GPy,Dapid/GPy,PredictiveScienceLab/GPy,beckdaniel/GPy,beckdaniel/GPy,maaskola/GPy,ptonner/GPy,gusmaogabriels/GPy,Dapid/GPy,strongh/GPy,avehtari/GPy,buntyke/GPy,esiivola/GPYgradients,ptonner/GPy,ptonner/GPy,SheffieldML/GPy,gusmaogabriels/GPy,ysekky/GPy,jameshensman/GPy,gusmaogabriels/GPy,strongh/GPy,PredictiveScienceLab/GPy,dhhjx880713/GPy,befelix/GPy,avehtari/GPy,PredictiveScienceLab/GPy,SheffieldML/GPy,beckdaniel/GPy,maaskola/GPy,TianpeiLuke/GPy,buntyke/GPy