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