Make psql use all pretty print options

Hi,

This patch finishes off the work that I did with making view
definitions use pretty printing.

It does:

* Pretty check constraints
* Pretty index predicates
* Pretty rule definitions
* Uppercases PRIMARY KEY and UNIQUE to be consistent with CHECK and
FOREIGN KEY
* View rules are improved to match table rules:

        View "public.v"
  Column  |  Type   | Modifiers
----------+---------+-----------
 ?column? | integer |
View definition:
 SELECT 1;
Rules:
 r1 AS
    ON INSERT TO v DO INSTEAD NOTHING
 r2 AS
    ON INSERT TO v DO INSTEAD NOTHING

Chris