add header files explicitly so "gradlew assemble" could finish

eyes-two/src/main/jni/imageutils/blur.cpp

@@ -33,7 +33,9 @@
 // to process a single image is ~5 milliseconds.
 
 #include <math.h>
-
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include "blur.h"
 #include "utils.h"
 

eyes-two/src/main/jni/imageutils/similar.cpp

@@ -32,6 +32,7 @@
 //
 // For performance consideration, 480x480 of central area of
 // a given image is used for signature computation.
+#include <string.h>
 
 #include "similar.h"
 #include "utils.h"