Add vtkSMPropertyGroup class

This adds a new class named vtkSMPropertyGroup which groups
together a set of vtkSMProperty objects.

Change-Id: I30dfe39ac52d328d692b1530576a850bc1ed3e59
Add PanelVisibility option to vtkSMProperty

This adds a new string member variable to the vtkSMProperty
class which controls the property's panel visibility. By default
all properties are set to have "advanced" panel visibility.

Change-Id: I180c2842846d1ae06821e4fc0a3a9492effc8224
Add support for property groups to vtkSMProxy

This adds support for accessing and storing property groups
in the vtkSMProxy class.

Change-Id: I2a3103840b62d48a0547804210956b89ca1dfe4a
Add panel visibility tags for sources.xml

This adds panel_visibility tags for the properties in sources.xml.

Change-Id: I4ca18f7c05bc3aef020bd108c222da171d7e9655
Add panel visibility tags for Spy Plot reader

This adds panel_visibility tags for the properties in
the Spy Plot reader.

Change-Id: Id4235c16dbe5baa55b932dd3b5f29a379694981d
Add panel visibility tags for the Transform filter

This adds panel_visibility tags to the properties in the
Transform filter.

Change-Id: I114eb0e2db429de024372232f8cb706e2fdfa0d0
Add panel visibility tags for views and representations

This adds panel_visibility tags for the views and representations.

Change-Id: I4b78f56361240cbd8af225f7001d7fafabae5847
Allow changing 'UseUncheckedProperties' flag on pqPropertyLinks

This adds the ability to changed the UseUncheckedProperties flag
in the pqPropertyLinks class. Previously this was not allowed and
a warning message was displayed when attempted.

Change-Id: Ib2efc87f5460e00feae28a45a81fecfeaad99db5
Add pqPropertyWidget class

This adds a new abstract base class which represents a
widget that controls a vtkSMProperty.

Change-Id: Ib9a5e6ef6ffb2c3139f984474fdfc5a5a42ee707
Add pqIntVectorPropertyWidget class

This adds a new property widget class which can represent
int vector properties.

Change-Id: Ib450777349c983d7f38e8823873b749dbfea3f3c
Add pqDoubleVectorPropertyWidget class

This adds a new property widget class which can represent a
double vector property.

Change-Id: I14552f4b86de1a99cab7451b686822338a2472cc
Add pqStringVectorPropertyWidget class

This adds a new property widget class which can represent a
string vector property.

Change-Id: Idf69425e99cf89d195ae5fab804d4f8389eac8e7
Fix whitespace issue in pqNamedWidgets

Change-Id: Ia498432f322e431abddfd9efe8ffc6188cf27687
Add pqProxyPropertyWidget class

This adds a new property widget class which can represent
proxy properties.

Change-Id: Idc74398c832f9aebb39b8e81122c342cd9bc0609
Add pqObjectPanelPropertyWidget class

This adds a new property widget class which adapts old object
panels into a property widget.

Change-Id: I27e0c4ec765ff1e93a7c1cf7e89671e6e5820b64
Add pqDisplayRepresentationPropertyWidget class

This adds a class which adapts the pqDisplayRepresentationWidget
class to be a property widget.

Change-Id: Id9bfc68f68327a18ba570cdb323bc6571fa59c5f
Add pqPropertiesPanel class

This adds a new properties panel widget. This new widget combines
the functionality of the old properties and display widgets into
a single panel.

Change-Id: I0455df1c94cabc97b433ac1374f572c3185e1e6b
Add pqColorEditorPropertyWidget class

This adds a new property widget which controls the various
color properties of a representation.

Change-Id: I78f6b0894796b3f7abf73bb1dde2fcbb8c66fb85
Add pqCubeAxesPropertyWidget class

This adds a new property widget which controls the
visibility and settings for cube axes.

Change-Id: I6c2a307a02e7dca4988e4ad766e93eebbae3ad20
Add pqStandardPropertyWidgetInterface class

This adds a new property widget interface class which creates
the standard property widgets (e.g. Color Editor and Cube Axes).

Change-Id: I2e015f82dc4d45a6210239aafb57e7da603715bf