add in reg.conf for configuration demo

demo/regression/reg.conf

@@ -0,0 +1,37 @@
+boost_iterations=10
+
+save_period=0
+
+train_path=
+					
+model_dir_path=
+
+validation_paths=
+
+validation_names=validation
+
+test_paths=
+
+test_names=test
+
+booster_type=1
+
+do_reboost=0
+
+bst:num_roots=0
+
+bst:num_feature=3
+
+learning_rate=0.01
+                
+min_child_weight=1
+                
+min_split_loss=0.1
+                
+max_depth=3           
+                
+reg_lambda=0.1
+
+subsample=1
+                
+use_layerwise=0