Update perlin noise function in uncertainty shader

This updates the perlin noise function in the uncertainty
surface painter fragment shader.

Change-Id: Ie558d0b26b3a93ee9019707514b8d67d02e40446
Merge topic 'perlin-noise' into next

b518ed9 Update perlin noise function in uncertainty shader
Eliminate shadowed-variable warnings.

Change-Id: I327156c6b53a43cd7c95ff33d63ffb9a08180921
Merge topic 'scalarbar_from_vtk' into next

bdccff4 Eliminate shadowed-variable warnings.
Bring in fixes from VTK head.

Specifically, bring in fixes to vtkScalarBarActor
so that annotations are drawn properly on horizontally-
oriented scalar bars.

Change-Id: I778e6f163e541b036ce47d89db63237cb6da78cd
Merge topic 'nudge-vtk' into next

6ae2da1 Bring in fixes from VTK head.
Fix compilation error with glActiveTexture() on windows

This fixes a compilation error in vtkUncertaintySurfacePainter
by using the functions from vtkgl instead.

Change-Id: I167081c77381017df3dfc139b30c667dda785cc0
Merge topic 'perlin-noise' into next

0bd609e Fix compilation error with glActiveTexture() on windows
Fix bug when finding vtkgl::ActiveTexture()

This fixes some issues in which the ActiveTexture() function
was not always being found.

Change-Id: I680df82b38023f1f365299bd3475dff0fc25529f
Merge topic 'perlin-noise' into next

03cd7c4 Fix bug when finding vtkgl::ActiveTexture()
Making panel_widget attribute consistent.

PropertyGroups and Properties used different attributes to specify the type of
widget to use. Changing the attribute used by PropertyGroups (type) to be same
as the other (panel_widget).

Change-Id: I2910a3de34c9bb488fd638b6e9f5ebd3f0f33014
Merge topic 'panel_cleanups' into next

3fda6c5 Making panel_widget attribute consistent.
Cleanup documentation.

Change-Id: I7049cfad0f14f05de8db9b1cf6057179390b7e7e
Merge topic 'panel_cleanups' into next

b690d97 Cleanup documentation.