Add sodium_init(), sodium_reinit() and sodium_shutdown()

README.markdown

@@ -73,6 +73,19 @@ A convenience header includes everything you need to use the library:
 
     #include <sodium.h>
 
+Before doing anything else with the library, call:
+
+    sodium_init(NULL);
+
+And if you need to release memory and other resources possibly
+allocated by the library, call:
+
+    sodium_shutdown();
+
+After fork()ing, call:
+
+    sodium_reinit();
+
 Sodium also provides helper functions to generate random numbers,
 leveraging `/dev/urandom` or `/dev/random` on *nix and the cryptographic
 service provider on Windows. The interface is similar to

src/libsodium/include/Makefile.am

@@ -1,6 +1,7 @@
 
 SODIUM_EXPORT = \
 	sodium.h \
+	sodium/core.h \
 	sodium/crypto_auth.h \
 	sodium/crypto_auth_hmacsha256.h \
 	sodium/crypto_auth_hmacsha512256.h \

src/libsodium/include/sodium.h

@@ -1,7 +1,8 @@
 
-#ifndef sodium_H
-#define sodium_H
+#ifndef __SODIUM_H__
+#define __SODIUM_H__
 
+#include <sodium/core.h>
 #include <sodium/crypto_auth.h>
 #include <sodium/crypto_auth_hmacsha256.h>
 #include <sodium/crypto_auth_hmacsha512256.h>