Bulk insert, onPost methods, and removal of final method declarations

Add bulkInsert method that does all inserts in one operation, and returns the correct number of records inserted.

Remove final method declarations so generated classes can be extended.  Also modify some variable declarations to be protected.

Add onPost methods for insert, update, bulkInsert, and delete methods so extending classes have an opportunity to run custom code after these events have occurred.
I like it!!!