Upstream

Removes duplicates from phonebook list view
when contact belongs to several groups,
now without using aggregate functions specific to any rdbm.

 It's a second try :-) I've consulted my my experts and they said that there is two ways:
 a) define own aggregate function which will work in all rdbms
 b) use several queries and don't worry about load - the load depends on queries volume but not on queries count..