val.toString() undefined

For anything the touches the db now, I'm getting this error. Seems to be something new. Perhaps related to a recent release. When I rollback everything except juggling, it works.

```
2014-01-24T00:22:51 app[web.1]: /app/node_modules/jugglingdb-postgres/lib/postgres.js:213
2014-01-24T00:22:51 app[web.1]: return escape(val.toString());
2014-01-24T00:22:51 app[web.1]: ^
2014-01-24T00:22:51 app[web.1]: TypeError: Cannot call method 'toString' of undefined
2014-01-24T00:22:51 app[web.1]: at PG.toDatabase (/app/node_modules/jugglingdb-postgres/lib/postgres.js:213:23)
2014-01-24T00:22:51 app[web.1]: at PG. (/app/node_modules/jugglingdb-postgres/lib/postgres.js:148:32)
```

The error occurs in jugglingdb-postgres/lib/postgres.js at line 213 where val.toString() is called on an undefined value. Examine the toDatabase method and the surrounding code to understand what data flow leads to an undefined 'val'. Check recent changes in the jugglingdb core that might affect property serialization. Running the project's PostgreSQL-related tests will help reproduce and verify the fix.

Rédigé par le modèle d'indexation à partir du texte de l'issue.