Fixed x & y coords less than 0

AlexeyAB

2017-03-17 71a9929af6c3d3ffb9527bb921c5cc4a20971ff6

 src/convolutional_layer.c

@@ -8,6 +8,10 @@
#include <stdio.h>
#include <time.h>

#ifdef CUDNN
#pragma comment(lib, "cudnn.lib")  
#endif

#ifdef AI2
#include "xnor_layer.h"
#endif