Merge Rust, C and C++ SDKs (#4)

* Generate native bindings from rust crate

* Add native instance and runtime statics

* Update README.md

examples/c/main.c

@@ -0,0 +1,14 @@
+// Copyright (c) Tribufu. All Rights Reserved.
+
+#include <stdio.h>
+#include <tribufu/api.h>
+
+int main(int argc, char **argv)
+{
+    tribufu_api_initialize();
+    char *version = tribufu_api_get_user_agent();
+    printf("%s\n", version);
+    tribufu_free_string(version);
+    tribufu_api_shutdown();
+    return 0;
+}