ENH: Use GatherV in CollectInformation()

This commit re-implements the CollectInformation() method
of the vtkPVSessionCore class to use MPI GatherV collective
operation when communicating information (vtkPVInformation)
from the satellite ranks to the root node, rank 0.

Change-Id: I757c53f5365e2f2f9f9d6bcef051cdd008151efa
Use the property key instead of XML name in JSON paths

The property key is the exposed name for a property that is possibly
defined in a subproxy. Using this name makes it possible to set
defaults for these exposed properties, which wasn't possible before
for properties whose exposed name was different from the XML name.

Change-Id: If3e98511f9bce4023cc68b1f8d33bd8bb10413e2
Fix incorrect setting of XML name for exposed properties

Exposed properties from a subproxy were *almost* able to support
default values different from the subproxy's definition, but not
quite. The XML name was overwritten by the exposed name, which caused
updates from the Qt side to not propagate to the server. This patch is
a little bit of a hack that resets the XML name after the exposed
proxy XML attributes have been processed.

Change-Id: I3a99a1104b16436be3882170c982ce3b8a341798
Moved some custom property values to XML

Now that default values can be specified for exposed properties of
subproxies, moved custom default for color legend font sizes to
XML.

Change-Id: Iada427a2269c52af119281e562648637ae0e43c7
Improve pqProxyWidgetDialog sizing

Change-Id: I19b196ccee8084a8ce44a3d6026bf34b7d09dea3
Marked some properties with no_custom_default attribute

This prevents these setting values from being saved to the
user settings file.

Change-Id: I5023cfd99ccfb6a4c49d4333b09bcc551a29351a
Add buttons to pqProxyWidgetDialog

Added a button to save currently applied settings as property defaults
and a button to restore the application defaults.

Removed QDialogButtonBox and replaced with simple QPushButtons.

Updated tests that involve the pqProxyWidgetDialog.

Change-Id: Iedc7684af5741b0854470ace3dcb459e5d523999
Merge topic '14771_fix_global_annotation_filter'

b4a19dca BUG: 14771: Fix Annotate Data filter in parallel.
7a59d796 Fixed "Field Data" missing from Spreadsheet panel.
Merge topic '14784_PythonCatalyst_better_IO'

737ca051 Making only process 0 check if the Catalyst script exists.
Merge topic 'fix_cmake_warnings'

fed7bb16 Fix cmake warnings about mixed link types in target_links.
Merge topic 'fix_size_hint_pqTreeView'

f82e558b Fix size hint for pqTreeWidget
Merge topic 'misc_chart_panel_fixes'

ac0c3353 Cleanup view properties panel.
1c8c07cb Fix handling of opacity/alpha channel in pqColorSelectorPropertyWidget.
Merge master into next

* commit 'aa525d5d662ea6c7036e47a07e4c8a146a773e5f':

Change-Id: I44ad3c16cd4215f5294811786ac9bf27e1ae9e71
BUG #14244: Fix stereo image capture.

Bring in VTK fix for the bug. At the same time, addresses other errors
raised when saving stereo image as the default stereo type ended up
being set to CrystalEyes.

Change-Id: I15b949fdf0587b1bb14117082dff4db3a9870d0b
Merge topic '14244_fix_stereo_image_captures' into next

581f96e6 BUG #14244: Fix stereo image capture.
Merge topic '14762_save_color_legend_settings' into next

6b645ec3 Add buttons to pqProxyWidgetDialog
6c297040 Marked some properties with no_custom_default attribute
fb790eda Improve pqProxyWidgetDialog sizing
8b7a741d Moved some custom property values to XML
c0003773 Fix incorrect setting of XML name for exposed properties
13242e10 Use the property key instead of XML name in JSON paths
Cleaning point sprite plugin

A warning was caused by a redefined signal in a child class.
Another warning was caused by a call to a property which
does not exist any more.

Change-Id: I2edf10921807230becf0f28edec2b076e3c662d4
Merge topic 'cleaning_point_sprite' into next

d4d4adb7 Cleaning point sprite plugin
plugins: initialize static plugins earlier

Change-Id: I95ccfa0e10ef5176d78921cc66a7ed3cb7cdc6c4
Merge topic 'static-plugin-loading' into next

cb009429 plugins: initialize static plugins earlier