Fixed detection and validate(recall, map) for .png and .bmp images.

AlexeyAB

2018-04-19 c2c8595b083ec3586a99bb913b8a986e81e3a42a

 build/darknet/x64/yolo-voc.cfg

@@ -256,3 +256,4 @@
absolute=1
thresh = .6
random=1