so remove them from MergeJoin node.  Hack together a partial
solution for commuted mergejoin operators --- yesterday
a mergejoin int4 = int8 would crash if the planner decided to
commute it, today it works.  The planner's representation of
mergejoins really needs a rewrite though.
Also, further testing of mergejoin ops in opr_sanity regress test.

it is now only mergejoin.

members to be clearer.  Fix cost computation for these.

New PARAM_EXEC type.

Pass List* of Aggregs into executor, and create needed array there.
No longer need to double-processs Aggregs with second copy in Query.

Fix crash when doing:

	select sum(x+1) from test where 1 > 0;

Another PGINDENT run that changes variable indenting and case label indenting.  Also static variable indenting.

This gets us a clean compile of 'common' and 'gist' with *clean* #include
files

	#include "postgres.h"
	#include "c.h"

	- centralizing to simplify the -I's required to compile