make it easier to change dendrogram edge width

Extend the API of vtkDendrogram & related classes so that it is easier
to change how wide the edges of the trees are drawn.

Change-Id: I6a6689319547c07d496860c9bb78ce836f21b0b3
Update TestTreeHeatmapItem for line width changes

As tree edge width is no longer hardcoded, we need to update this
affected test so that its resulting image remains the same.

Change-Id: I28980f6348646d8c7ec6c986eab846b86ac21dcd
Updates to the FFMPEG code, modernizing and improving

Make use of the check_c_source_compiles macro, added a check for
the renamed AVCodecId (was CodecId) and moved the test code to being
inline.

Change-Id: I699f51a9dec0452f4bc53c41bb143ecd777d5249
Merge topic 'ffmpeg-update' into master

5b39c918 Updates to the FFMPEG code, modernizing and improving
Merge topic 'set_tree_edge_width' into master

02f7a43f Update TestTreeHeatmapItem for line width changes
98a5b2a1 make it easier to change dendrogram edge width
Refactor vtkExtractCTHPart.

Cleanup vtkExtractCTHPart to use VTK 6.0 enhancements. Also exposed API to
control removal of ghost cells/capping/triangulation. Not removing ghost-cells
overcomes holes inherent in the algorithm employed.

Change-Id: I61f3abd4dc93067e4bdc7921d7247e033814e11a
Merge topic 'fix_extract_cth_filter' into master

323ad383 Refactor vtkExtractCTHPart.
ati projected tetra bugs

Clean up "invalid operation" OpenGL error reported
on AMD Radeon dashboards. Removed extra framebuffer
and renderbuffers allocation and leak. Match internal
multisampling paramters to the default FBO. For FBO
blit they must match. Added IsSupported methods to
test for extension/driver support. Disabled the class
for non Apple AMD Radeon devices because the ctests
take > 30min and do not produce correct result. It
looks to me like AMD drivers have a texturing related
bug. Clean up a couple deviations from VTK coding
standard.

Change-Id: Ie1cbfab46a117c16c2731a29dd2f3829daeffaa8
Merge topic 'amd-projected-tetra' into master

60fbcda9 ati projected tetra bugs
Make sure if Webgl trigger exception it won't prevent other modules to load

Change-Id: Ibf5efc99acd964eb35ce9d730800581c6f874109
Merge topic 'vtkweb-prevent-webgl-error' into master

31ae28cf Make sure if Webgl trigger exception it won't prevent other modules to load