Intermediate work commit. 

Build the ValuesHKey and test, which passes.

Replace all instances of PersititHKey with HKey, so there is only one
(or two) places to replace to use ValuesHKey vs Persistit. 

Still too many instaces of Key being used, but now somewhat reduced. 

The larger IT tests don't pass, I'm still missing something about
conversion of HKey to Key for reading that doesn't get correct rows.
Fix ValuesHKey copyTo() to not copy/bother with the unset values as they
are important to the HKey use for scan start/end processing.
Find one more place where PersititHKey can be replaced by row.HKey. 

Fix the Store which also want to have the newHKey() interface, though
its never used.
Have the Store implemetation of newHKey() which should never be used,
throw an error.
Re-order the ValuesHKey methods.
Get FDBGroupCursor inner classes to correctly set the HKey key values
for the StoreData from the new ValuesHKey implememntation.
Because the HKey is no longer assumed to have a Persistit Key embedded,
update the hkey() method to copy the value.
Merge remote-tracking branch 'github/master' into Implement-new-HKey
Add an extra check to the toString() method to output rows which may not
have all the values without throwing an error.
Remove redundant code from Flatten_HKeyOrdered. There's no reason to
derive these values if they're kept (now correctly) in the HKey itself.
Fix the extendOrdinal()/extendWithNull() used by the flattenHKey
process, usually as part of the write indexes. This correctly extends
the HKeys if you extend more than one level in the key at a time. 

Add a toString() method to allow many tests to pass correctly.
Remove some dead code.
Remove some dead code, unused variables, and imports.
Fix test to correct long->int variables
Remove the last of the calls to HKey.key(), because the implementation
(ValuesHKey) does not keep an underlying Persistit Key, but creates it
on demand.
Make the adapters newHKey() return the ValuesHKey, not the
PersistitHKey.
Remove the HKey#key() implementation as no longer used.
Update the ValuesHKey to use the TComparison interface as generated and
kept by the TypesRegistryService. This provides a TKeyComparable
interface for comparing and/or copying values which are KeyComparable
(e.g. INT and BIGINT) but not handled correctly by direct Value copy.
Update HKeyRow_Default#buildHKeyRow() to use a new ValuesHKey interface
to allow copying of TKeyCompatible values. This fixes several test
issues.
Merge remote-tracking branch 'github/master' into Implement-new-HKey

Conflicts:
	src/test/java/com/foundationdb/server/test/it/qp/FlattenIT.java