Refactoring color scale editor.

Refactoring color scale editor widget. Instead of modal dialog, we now use a
dock-panel to edit color and opacity transfer functions. pqColorMapEditor, the
new color editor widget, is similar to the properties panel, where
pqPropertyWidget subclasses are used to control properties on the LookupTable
(and PiecewiseFunction) proxies instead of writing custom logic. Similarly, the
editor to edit properties on the scalar-bar is also auto-generated.

Added new types of pqPropertyWidget subclasses viz. pqColorOpacityEditorWidget,
pqColorAnnotationsPropertyWidget that enable editing transfer functions and
annotations on the lookup table proxy. Also added pqFontPropertyWidget for
editing text/font releated properties.

vtkSMPropertyGroup is now extended to add support for adding roles or functions
to properties in the group, thus making it possible to write pqPropertyWidget
widgets that don't directly depend on property names.

The old/deprecated classes viz. pqColorScaleEditor and
pqTransferFunctionChartViewWidget are now moved to new module pqDeprecated,
where we can collect all obsolete classes before purging them.

Also updates tests to use the new color map editing functionality.

Change-Id: I8afee77e9d587c078d3cfb740e61f80077d05ff9
Fix transfer function rescale in log-scale mode.

When loading color-maps or rescaling transfer function points when log-scale was
enabled, we do all the necessary interporlations in log-space. ApplyColorMap(),
InvertTransferFunction(), and RescaleTransferFunction()  now respect log-scale
mode.

Also fixed entering in and out of log-space. Now when user click "use-log-scale"
check box, the control points are respaced in the requested space so that the
transfer function appears the same (though the mapping changes). Added a new
test (LogColorMap) to test for log-color maps.

Change-Id: I67f13abd394cdb2fbe2a710b51f209f066291ab0
Update VTK to bring in VTK API changes.

Change-Id: I678eebd570d7f69a739b364d4b3e76c9c1d1279d
Merge topic '13082_fix_log_lut' into next

327559c Update VTK to bring in VTK API changes.
b9e0e3a Fix transfer function rescale in log-scale mode.
a9e8704 Refactoring color scale editor.