PRD-5327 - Not implementing Serializable prevents copy&paste of reports 

Original case: http://jira.pentaho.com/browse/PRD-5327?filter=12774

To implement Copy&Paste in a safe way, PRD serializes reports and elements. Reports that contain a OpenERP data-source are not serializable, as the OpenERPConfiguration and associated classes are not serializable. PRD does not care about long-term storage, we just want to get data in and out of the system clipboard. So short-term serialization is fine. 

The fix is simple: Implement Serializable for the OpenERPConfiguration object and its contained objects. All properties should be safely serializable once they implement the java.io.Serializable interface. 

Only the OpenERPFilterInfo has one non-serializable field for the "value". But from the code it seems as it will only ever contain strings, or maybe other primitive objects. It seems OK to just declare that class serializable and hope that no user ever puts something in there that is not serializable.