new option to color the tree based on vertex data

New functionality introduced in this commit allows us to draw each line
in the tree with a color specified by the target vertex.  This is
accomplished by calling the new function SetTreeColorArray().

The parameter of this function specifies the name of a vtkDoubleArray
within the tree's VertexData.  The values of this array are used as the
key of a color lookup table.

Change-Id: I4c6d20f90b5791e2ce0e57ea86ad05f742a13449
Fix thread-safety issue in vtkImageData::GetDimensions()

This fixes a thread-safety issue in the vtkImageData::GetDimensions()
method. The thread-safe version (which takes a pointer to the output
array) was calling the non-thread-safe version causing both to not be
thread safe. The calculation of the dimensions was moved to the thread-
safe version so it can now be reliably called from multiple threds.

Change-Id: I156d6e196c5b7a0ab4654941a646dfad4e4cfefe
Change vtkVolumeMapper to use thread-safe GetDimensions()

This changes the ConvertCroppingRegionPlanesToVoxels() method in
the vtkVolumeMapper class to use the thread-safe version of the
GetDimensions() method in the vtkImageData class.

Change-Id: Ieeffe7bc79e4023859cfd38d0469bf6521bb8252
Fix thread-safety issue in vtkInformationVector

This changes the SetNumberOfInformationObjects() method in the
vtkInformationVector class to only set the number of information
objects if it is different from the current number of objects.

This fixes an issue in which multiple threads calling the
vtkExecutive::GetOutputInfomation() method would result in
SetNumberOfInformationObjects() being called simultaneously.

Change-Id: Ib39818d163ffa514308c72489cfaa2dcac9cd7fa
Fixed issue of using the wrong size for a vtkTypeInt64.

Change-Id: Idb5bb56a047e9dab57e47cab557ccf0e7ec98510
ENH: Render stacked plots as separate colors in legend

Modified python test to verify functionality

Change-Id: I855c853fc4b56d958108e49977432fd0b52e462e
Merge topic 'fix-threading-issues' into master

e4a793c4 Fix thread-safety issue in vtkInformationVector
79ce76e7 Change vtkVolumeMapper to use thread-safe GetDimensions()
4345f286 Fix thread-safety issue in vtkImageData::GetDimensions()
Merge topic 'color_tree' into master

eac2ae01 new option to color the tree based on vertex data
Fix leaks that valgrind found

Change-Id: I1a3918991fc5db1f6241309eacfc354a7f303e16
Merge topic 'AddShowLegendToTest' into master

f1df9cc5 ENH: Render stacked plots as separate colors in legend
Improve Java wrapping library loading error reporting

Rather than swallowing UnsatisfiedLinkErrors print the
stack trace to stderr. If explicitly loading a library
using a full path first check if file exists, only try
to load if it exists.

Change-Id: I67066e1c9377c0421bac73d0c0a769cc45300e51
Merge topic 'fix_windblade_memleaks' into master

f1d8aeea Fix leaks that valgrind found
Only allow selection on visible blocks

This updates the composite poly data mapper to only allow
selections for visible blocks.

Change-Id: Ib971062717dcb056e65f0adc42ff012d9892c0bf
Fix display attribute handling in vtkCompositePainter

This fixes the handling of applying block display attributes
in the vtkCompositePainter::RenderBlock() method.

Change-Id: I61a3bf2085266b87868af3dc6548bff319ab186c
Zero initialize values in vtkGradientFilter

This fixes a "Conditional jump or move depends on uninitialised
value(s)" error from valgrind by zero initializing the values at
the top of ComputeGradientsSG().

Change-Id: Idfc249ed797c798a9bd79ece2883ca48d9735afb
Merge topic 'zero-initialize-in-gradient-filter' into master

d33f2b8c Zero initialize values in vtkGradientFilter
Merge topic 'java-native-lib-loading' into master

e748e467 Improve Java wrapping library loading error reporting
BUG: Vertext list leak

vtkPLY allocates a list of vertices for each face. That list was not
freed after it was used in vtkPLYReader.

To further compilate things, vtkPLY::ascii_get_element and
vtkPLY::binary_get_element used two different forms of heap allocation.

Change-Id: Ic92d3b9dd3291576a8ce285e905db760cbf7f23b
Merge topic 'composite-data-display-attributes' into master

3dd5f751 Fix display attribute handling in vtkCompositePainter
82aee804 Only allow selection on visible blocks
Merge topic 'PLYReader_Leak' into master

af106289 BUG: Vertext list leak