Add open() and close() skeletons that only recognize the image as a correct one.

include/dicformat/context.h

@@ -0,0 +1,20 @@
+//
+// Created by claunia on 17/03/19.
+//
+
+#ifndef LIBDICFORMAT_CONTEXT_H
+#define LIBDICFORMAT_CONTEXT_H
+
+#include <stdint.h>
+#include <stdio.h>
+
+typedef struct dicformatContext
+{
+    uint64_t  magic;
+    uint8_t   libraryMajorVersion;
+    uint8_t   libraryMinorVersion;
+    FILE      *imageStream;
+    DicHeader header;
+} dicformatContext;
+
+#endif //LIBDICFORMAT_CONTEXT_H