PATCH: recursive json_populate_record()

Hi.

The first attached patch implements recursive processing of nested 
objects and arrays in json[b]_populate_record[set](), 
json[b]_to_record[set](). See regression tests for examples.

It also fixes the following errors/inconsistencies caused by lost 
quoting of string json values:

[master]=# select * from json_to_record('{"js": "a"}') as rec(js json);
ERROR:  invalid input syntax for type json
DETAIL:  Token "a" is invalid.
CONTEXT:  JSON data, line 1: a

[master]=# select * from json_to_record('{"js": "true"}') as rec(js json);
   js
------
true

[patched]=# select * from json_to_record('{"js": "a"}') as rec(js json);
   js
-----
  "a"

[patched]=# select * from json_to_record('{"js": "true"}') as rec(js json);
    js
--------
  "true"


The second patch adds assignment of correct ndims to array fields of 
RECORD function result types.
Without this patch, attndims in tuple descriptors of RECORD types is 
always 0 and the corresponding assertion fails in the next test:

[patched]=# select json_to_record('{"a": [1, 2, 3]}') as rec(a int[]);


Should I submit these patches to commitfest?

-- 
Nikita Glukhov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company