pgsql: Include planning time in EXPLAIN ANALYZE output.

Include planning time in EXPLAIN ANALYZE output.

This doesn't work for prepared queries, but it's not too easy to get
the information in that case and there's some debate as to exactly
what the right thing to measure is, so just do this for now.

Andreas Karlsson, with slight doc changes by me.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/9347baa5bbc70368f2f01438bbb8116863dac1ec

Modified Files
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doc/src/sgml/perform.sgml      |   27 +++++++++++++++++++++++++++
doc/src/sgml/ref/explain.sgml  |   17 ++++++++++++-----
src/backend/commands/explain.c |   24 +++++++++++++++++++++---
src/backend/commands/prepare.c |    2 +-
src/include/commands/explain.h |    4 ++--
5 files changed, 63 insertions(+), 11 deletions(-)