pgsql: psql: Improve \pset without arguments

psql: Improve \pset without arguments

Revert the output of the individual backslash commands that change print
settings back to the 9.3 way (not showing the command name in
parentheses).  Implement \pset without arguments separately, showing all
settings with values in a table form.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/6895866510c5f4185f50ae7d6810d9ffd7701a9e

Modified Files
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src/bin/psql/command.c             |  189 +++++++++++++++++++++++++++---------
src/test/regress/expected/psql.out |   36 +++----
2 files changed, 161 insertions(+), 64 deletions(-)