Enhancement - Path integration

- Implemented Path::operator (std::string) const, to provide an
  automatic cast to std::string for any Path, File or Directory.
- Made use of new cast in various code.
- Changed use of spaces in atoi () calls.
- Switched from std::string::data () to std::string::c_str () calls.

src/Config.cpp

@@ -321,7 +321,7 @@ void Config::parse (const std::string& input, int nest /* = 1 */)
           if (included.is_absolute ())
           {
             if (included.readable ())
-              this->load (included.data, nest + 1);
+              this->load (included, nest + 1);
             else
               throw std::string ("Could not read include file '") + included.data + "'";
           }