ObjectManagerFactory responsible for creation of ObjectManagers for persistence of objects to datastores.
Will typically be either extended or utilised by PersistenceManagerFactory (JDO) or EntityManagerFactory (JPA).
version: $Revision: 1.15 $
Method to initialise the OMFContext.
This should be performed after setting any persistence properties that affect the content
of the OMFContext (e.g PluginRegistry, ClassLoaderResolver, etc).