Major refactoring of structures, with unit tests.

host/linktest/main.c

+#include <stdio.h>
+
+#include "host_common.h"
+
+int main(void)
+{
+  /* host_key.h */
+  PrivateKeyRead(0, 0);
+  PrivateKeyFree(0);
+  PublicKeyInit(0, 0, 0);
+  PublicKeyAlloc(0, 0, 0);
+  PublicKeyCopy(0, 0);
+  PublicKeyRead(0, 0, 0);
+
+  /* host_signature.h */
+  SignatureInit(0, 0, 0, 0);
+  SignatureAlloc(0, 0);
+  SignatureCopy(0, 0);
+  CalculateChecksum(0, 0);
+  CalculateSignature(0, 0, 0);
+
+  /* host_common.h */
+  CreateKeyBlock(0, 0, 0);
+  CreateFirmwarePreamble(0, 0, 0, 0);
+  CreateKernelPreamble(0, 0, 0, 0, 0, 0);
+
+  return 0;
+}