converted executable-based commands to the new command API (as "core")

include/cellar.hpp

@@ -1,9 +1,14 @@
 #ifndef __CELLAR_HPP
 #define __CELLAR_HPP
 #pragma once
+#include <string>
+#include <vector>
+
+using namespace std;
 
 namespace cellar {
-    void print_header();
+    extern void print_header();
+    extern void print_version(int,vector<string>);
 }
 
 #endif // __CELLAR_HPP

include/commands.hpp

@@ -14,6 +14,8 @@ namespace cellar {
 
         void add_command(string, CommandFunction);
         vector<string> list_commands();
+
+        extern map<string,CommandFunction> core_commands();
     }
 }