add some more doc to ConvolutionalLayer.cpp
add some more doc to ConvolutionalLayer.cpp

MiniLight/DeepCL,mrgloom/DeepCL,hughperkins/DeepCL,pimms/DeepCL,mrgloom/DeepCL,Peilong/DeepCL,FighterLYL/DeepCL,Peilong/DeepCL,hughperkins/DeepCL,MiniLight/DeepCL,mrgloom/DeepCL,Peilong/DeepCL,MiniLight/DeepCL,FighterLYL/DeepCL,Peilong/DeepCL,MiniLight/DeepCL,FighterLYL/DeepCL,hughperkins/DeepCL,Peilong/DeepCL,FighterLYL/DeepCL,mrgloom/DeepCL,pimms/DeepCL,pimms/DeepCL,hughperkins/DeepCL,hughperkins/DeepCL,pimms/DeepCL,mrgloom/DeepCL,MiniLight/DeepCL,FighterLYL/DeepCL,pimms/DeepCL