[PATCH] Add extra statistics to explain for Nested Loop

Hi, hackers.
For some distributions of data in tables, different loops in nested loop 
joins can take different time and process different amounts of entries. 
It makes average statistics returned by explain analyze not very useful 
for DBA.
To fix it, here is the patch that add printing of min and max statistics 
for time and rows across all loops in Nested Loop to EXPLAIN ANALYSE.
Please don't hesitate to share any thoughts on this topic!
-- 
Ekaterina Sokolova
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company