PHOENIX-1037 ResultSetSqlType for date/time types

Add implementations of getResultSetSqlType for unsigned
date/time/timestamp types
PHOENIX-1043 Add timezone conversion function

Contributed by Vaclav Loffelmann
PHOENIX-990 OOM caused by order by query returning all rows (PraveenMurugesan)
PHOENIX-1007 Replace getNextKeyHint(KeyValue kv) with getNextCellHint(Cell kv) in Filters. (Anoop)