pgAdmin 4 commit: This is a big one campers; Add initial support for tr

This is a big one campers; Add initial support for treeview nodes.

This commit adds the following:

- Storage of server groups in the configuration database
- Creation of a default server group on in the database
- A mechanism for plugging in treeview node types
- A node type for server groups with:
  - Treeview display
  - Custom per-node javascript implementing a menu option/dialogue to add new groups
  - Custom per-node CSS to style the treeview node
- JSON formatted data in response to AJAX requests, including:
  - Success/failure indication
  - Error message
  - Extra info (e.g. stack trace)
  - The original request data
  - Additional return data, e.g. node ID and label etc.

Branch
------
master

Details
-------
http://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=89cc11fb8075494160803a98e32a7c746c97ffcf

Modified Files
--------------
web/config.py                                      |    4 +
web/pgadmin/__init__.py                            |   11 ++-
web/pgadmin/about/browser.py                       |   26 ------
web/pgadmin/about/hooks.py                         |   26 ++++++
web/pgadmin/browser/__init__.py                    |   11 +++
web/pgadmin/browser/hooks.py                       |   51 +++++++++++
web/pgadmin/browser/nodes/server_groups/hooks.py   |   75 +++++++++++++++
.../server_groups/static/img/server-group.png      |  Bin 0 -> 504 bytes
web/pgadmin/browser/nodes/server_groups/views.py   |   64 +++++++++++++
web/pgadmin/browser/static/js/utils.js             |   39 ++++++++
web/pgadmin/browser/templates/browser/body.html    |   13 +--
web/pgadmin/browser/templates/browser/index.html   |    4 -
web/pgadmin/browser/views.py                       |   96 ++++++++++++++++----
web/pgadmin/settings/browser.py                    |   16 ----
web/pgadmin/settings/hooks.py                      |   16 ++++
web/pgadmin/settings/views.py                      |   51 ++++++++---
web/pgadmin/static/css/overrides.css               |   18 +++-
web/pgadmin/test/browser.py                        |   27 ------
web/pgadmin/test/hooks.py                          |   27 ++++++
web/utils/ajax.py                                  |   24 +++++
20 files changed, 483 insertions(+), 116 deletions(-)