Fix ON DUPLICATE KEY UPDATE with ENUM

Update JdbcDatabaseMetaData.getSQLKeywords() and perform some minor optimizations

Fix an issue with code coverage and building of documentation

re-enable some pagestore testing

by essentially copying over various fixes we made, from the MVStore class, to the RegularTable class

now that katzyn has fixed the underlying issue

Fix TCP version check

needs to throw a SQLException not a DbException

Assorted changes

#1097 reduce memory overhead of the group by data structures