Updated schema definition to conform to the new serialisation form
Use the primary constraint in the model if it is defined as such in the metadata
Adjust to appropriate key for the primary key
Added parsing of oracle inner forign key constraint
Widen the visibility of the parseField method so it can be overriden. Implement the parsing of primary key of oracle tables. This concludes #42.
Added test for internal primary key constraint
Added keyword primary
Fixed equals method to compare the field number and index number
Add test sql for inner oracle primary key
