Created a global macro value for arc resolution (per angle unit)

Change-Id: I6ed53c61754979195a1ba4b05751779e6e0e206b

Hybrid/vtkPolarAxesActor.cxx

@@ -704,7 +704,8 @@ void vtkPolarAxesActor::BuildPolarAxisLabels( double zeroThreshold )
   double thetaRad = vtkMath::RadiansFromDegrees( this->MaximumAngle );
   double cosTheta = cos( thetaRad );
   double sinTheta = sin( thetaRad );
-  vtkIdType arcResolution = static_cast<vtkIdType>( this->MaximumAngle / 5 ); 
+  vtkIdType arcResolution 
+    = static_cast<vtkIdType>( this->MaximumAngle * VTK_POLAR_ARC_RESOLUTION_PER_DEG ); 
   // Arc points
   vtkPoints *polarArcsPoints = vtkPoints::New();
   this->PolarArcs->SetPoints( polarArcsPoints );

Hybrid/vtkPolarAxesActor.h

@@ -35,6 +35,7 @@ All rights reserve
 #define VTK_MAXIMUM_NUMBER_OF_RADIAL_AXES 50
 #define VTK_DEFAULT_NUMBER_OF_RADIAL_AXES 5
 #define VTK_DEFAULT_MAXIMUM_POLAR_ANGLE 90.0
+#define VTK_POLAR_ARC_RESOLUTION_PER_DEG 0.2
 
 #include "vtkActor.h"