Create files for nbt library and a tool to use it.

These files were also used to figure out the process of building them so
their content is garbage.

src/lib/libnbt.cpp

@@ -0,0 +1,3 @@
+int blob() {
+    return 1;
+}

src/lib/libnbt.h

@@ -0,0 +1 @@
+int blob();

src/tools/dumpnbt.cpp

@@ -0,0 +1,5 @@
+#include "../lib/libnbt.h"
+
+int main(int argc, char* argv[]) {
+    return blob();
+}