pgAdmin 4 commit: Support "show system objects" in casts.

Support "show system objects" in casts.

Branch
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master

Details
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http://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=71badac203f3199e58eac1f45654d41a1bf52812
Author: Sanket Mehta <sanket.mehta@enterprisedb.com>

Modified Files
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.../servers/databases/casts/__init__.py            | 47 +++++++++++++++++-----
.../casts/templates/cast/sql/9.1_plus/create.sql   |  5 ---
.../casts/templates/cast/sql/9.1_plus/nodes.sql    | 23 +++++++++++
.../templates/cast/sql/9.1_plus/properties.sql     |  8 ++--
4 files changed, 64 insertions(+), 19 deletions(-)