make: Global change: Move all public headers to include folder.  Change source to including public headers using #include <ndn-cpp/*>. Split some header files to minimize exposing C .h files.
diff --git a/ndn-cpp/c/util/crypto.h b/ndn-cpp/c/util/crypto.h
index 5bec549..586108b 100644
--- a/ndn-cpp/c/util/crypto.h
+++ b/ndn-cpp/c/util/crypto.h
@@ -9,7 +9,7 @@
 
 #include <openssl/ssl.h>
 #include <openssl/rsa.h>
-#include "../common.h"
+#include <ndn-cpp/c/common.h>
 
 #ifdef __cplusplus
 extern "C" {