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/TDB.cpp

@@ -114,7 +114,7 @@ void TDB::location (const std::string& path)
           path +
           "' does not exist, or is not readable and writable.";
 
-  mLocations.push_back (Location (d.data));
+  mLocations.push_back (Location (d));
 }
 
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