Imcomplete changes. Using as an intermediate step, Still need to set
storage description for "hidden" sequence.
Basic setup complete, the AIS create/alter inserts the sequence
correctly, and it is, for some set of tests, working correctly. 

Remove the old AbstractStore.hiddenPKUpdate code. Which, in turn breaks
the ITs.
Remove DMLFunctions#convertNewRow() as it was unused.
Add a Store#writeNewRow() method for internal generated rows to write,
and capture the PK generation required for some of these row. Update the
ExternalDataService and FullTextService to use this new API for their
generated rows.
Remove the extra setting of the HiddenPK in NiceRow#toRowData() as the
order of the hanldling has changed. NiceRow is passed to AbstractStore,
the Hidden PK is added to Nice Row, then converted to RowData for
writing.
Move the point at which the identitySequence is added to the new table
during the merge to allow the grouping to work correctly with the new
hidden PK sequences.
Make Table#getIdentityColumn() search all the columns as the Hidden PK
is now an Identity column too. This is used to ensure the attached
sequence is correctly removed when the table is dropped.
Add new tests for ChangeValidator to ensure drop of PK colums
(with/without sequences) are correctly managed.
Update tests using row generation to no longer need to assume the
HiddenPK value of -1 in the no-pk tables. This is handled correctly now.
Update the RowData() method to ensure all fields (including the hidden
PK field) is copied correctly. Remove no longer used method and invalid
TODO comment.
Remove invalid TODO comments and unused LOG variables.
Next few tests to remove the setting of the autoinc column which
confuses the tests.
Change the hiddenPK sequence name to match the BasicDDLFunctions
tempoary name, and have AISMerge generate a real name. This causes other
test failures, but is now internally consistent.
Add a new AISValidation: Only one identity column per table, plus
exception and error message. 

Remove the Duplicate Sequence check in Sequence, as the alter table
adding a PK to a table with a no PK fails incorrectly.
Move the checkJoinTo to the AISInvariants to keep all the AISInvariants
in one place.
Remove the requirement for the FullTextService in this IT, as the test
does not require it. 

Update the exception being returned for two identiy sequences in one
test
Update the TypesRegistrySevice to use the SchemaTablesService (like all
the other services) to register the two types tables. The different path
with the updated hidden PK/Sequence incorrectly generates a sequence for
the in memory table. This new way is now correct, and consistent.
Update the doAddTable()/addTable() processing to set the group storage
information to allow the Table hidden PK processing to correctly
determine if the hidden PK needs a sequence or not.
Add or update tests affected by the changed alter table processing. The
auto-generated sequence name is different, and new tests to veriy that
adding or removing the auto-key works correctly.
Validate the intenrnal columns when altering a table.