Implemented saving gruntwork results to file.

* Monkey Skyway paths are now saved in a format compatible with
paths.json
* flush() is called on every periodic DB save in addition to the /flush
and /mss N export commands
* Monkeys now accept WIP routes

src/settings.hpp

@@ -20,6 +20,7 @@ namespace settings {
     extern std::string XDTJSON;
     extern std::string MOBJSON;
     extern std::string PATHJSON;
+    extern std::string GRUNTWORKJSON;
 
     void init();
 }