Add converions according to $class->properties[$name]['type']

In the ORM we have the Doctrine\DBAL\Types namespace that we have to mirror to Doctrine\ODM\CouchDB\Types. Methods would have to be "convertPhpToJsonValue()" and "convertJsonToPhpValue()" that need to be called during hydration and saving inside the Persister.

Possible Types for now:

• String (this is both VARCHAR + CLOB of DBs)
• Integer
• Array (uncasted values)
• Float/Double * Boolean