Merge pull request rasmusbergpalm#52 from ananda621/optional_bias_regularizer

optional bias regularizer

Author: rasmusbergpalm

NN/nnapplygrads.m

@@ -5,7 +5,7 @@
 
     for i = 1 : (nn.n - 1)
         if(nn.weightPenaltyL2>0)
-            dW = nn.dW{i} + nn.weightPenaltyL2 * nn.W{i};
+            dW = nn.dW{i} + nn.weightPenaltyL2 * [zeros(size(nn.W{i},1),1) nn.W{i}(:,2:end)];
         else
             dW = nn.dW{i};
         end