Added platform independent sleep function

src/openalpr/support/platform.cpp

@@ -0,0 +1,10 @@
+#include "platform.h"
+
+void sleep_ms(int sleepMs)
+{
+	#ifdef WINDOWS
+		Sleep(sleepMs);
+	#else
+		usleep(sleepMs * 1000);   // usleep takes sleep time in us (1 millionth of a second)
+	#endif
+}