feat: CLI-only version (without GTK)

Modify the build system and the source
files to support building a CLI-only
version with only glib2 as a dependency.
Use CLI_ONLY=1 ./configure, then make clean all.

method.c

@@ -58,7 +58,7 @@ void ListMethods(void)
    for(i=0; i<Closure->methodList->len; i++)
    {  Method *method = g_ptr_array_index(Closure->methodList, i);
 
-      strncpy(name, method->name, 4);
+      strncpy(name, method->name, 5);
       PrintCLI("%s -- %s\n",name,method->description);
    }
 }