Added comments about the danger of not clamping.

With clang's -fsanitize, several of VTK's tests
invoke undefined behaviour by converting doubles
to integer types that are out of range (ex: converting
12345.67 to uint8).  I have no fix, but these comments
will help anyone than runs into this.

Also improved debuggability and readability by adding
a temp local variable.

Change-Id: I0453b7bca693c416f7379f5b8c8cd60d0997937c
Fix clang warning about comparision that's always true.

Specifically:
/Common/DataModel/vtkGenericAttributeCollection.cxx:456:44: warning: comparison of array 'this->AttributesToInterpolate' not equal to a null pointer is always true [-Wtautological-pointer-compare]
                                  || this->AttributesToInterpolate!=0));
                                     ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~  ~

The warning is correct, so remove the unneeded check.  Also, it's only in an assert.

Change-Id: I74fa877da2b167ff32f2a568c3e9f71db82581ff
Add a documentation module that contains information keys

Eventually all vtkInformationKeys should be added to this module.  This
commit only gets some of the more common ones.

Change-Id: Ic1c116b190c20f108fc064d2dad1ee516ebf7626
vtkPythonAlgorithm: print out all the error information

Unfortunately, Python has this habit of using the name of the
exception's class for critical information and the stringification of
the exception itself is useless on its own (e.g., AttributeError's
string is just the name of the attribute that is missing). To get better
error information, use traceback.format_exception if it is available.

Change-Id: I7fcbd9a12e505b2e3422c31dcf52055d98144a64
Update to the upstream GLEW 1.11.0 release

Preserved upstream formatting etc for easier updates in the future.

Change-Id: I57bfc51c75c02ade4194b108470096078129e24d
Added logic for OSMesa contexts

This will enable VTK's GLEW to make use of OSMesa OpenGL contexts,
unfortunately support for this has yet to be merged upstream.

Change-Id: I6ead4a9f4ddd7276fdad806af6093343145307dd
jsoncpp: Update to use the seperate-file version

jsoncpp can be built as either a collection of source files or as a
single source file that is the "amalgamation" of all sources.  Some
compilers, PGI namely, cannot handle the amalgamation and will crash
with an internal compiler error.  Building the original seperate-files
version is easier for the compiler to deal with and can build
successfully.

Using df26dae from https://github.com/open-source-parsers/jsoncpp.git

Change-Id: Ie8610c35aeb8b18822bda54eb426a3bac6c796f7
vtkIOGeometry: Correct typos in older jsoncpp API calls

Change-Id: I26483d85a8c9a72faf75df2c6c5ef2dadf177c75
Merge topic 'better-vtkpythonalgorithm-error' into master

b0cd19ba vtkPythonAlgorithm: print out all the error information
Add support for OSMesa builds of OpenGL2

This commit makes some changes in Mesa's logic so that it can use
OSMesa's OpenGL context, and load extensions in OSMesa. This works
on Linux, but will need more work to get it working on Windows
and/or Mac OS X. Pulled out the OpenGL Mesa logic so that both GLEW
and vtkRenderingOpenGL2 can use it (and ensure it is consistent).

Change-Id: Ibdf6715f950929949f5055b3ddbd38b09d9b84d6
Merge topic 'update-and-breakup-jsoncpp' into master

250f3113 vtkIOGeometry: Correct typos in older jsoncpp API calls
21155458 jsoncpp: Update to use the seperate-file version
Fix illegal extent request in ImageThresholdConnectivity.

When asked for an output extent that was smaller than the input extent,
this filter would pass an illegal extent to GetScalarPointerForExtent().
It is possible that older versions of VTK would allow this, but in VTK 6
it raises an error.  It has a high probability of causing a segfault.

Change-Id: Ic024f9aa97335f1ba29b47be89a4e5be8195b00f
Merge topic 'imagethresholdconnectivity-segfault' into master

24265644 Fix illegal extent request in ImageThresholdConnectivity.
make sure modules are really turned off

Change-Id: I63d7e0b3c44b8050c4ce96a631e75a156b639e97
Merge remote-tracking branch 'origin/master' into glew

Conflicts:
	Rendering/OpenGL2/CMakeLists.txt

Change-Id: I984aa8000e0248fbc0c9c4870d3b35fbb2003df9
Merge topic 'fix_embedded_module_turnoff' into master

9d297337 make sure modules are really turned off
Merge topic 'Wtautological-warning' into master

985aab49 Fix clang warning about comparision that's always true.
Merge topic 'glew' into master

207c2594 Merge remote-tracking branch 'origin/master' into glew
c0dee401 Add support for OSMesa builds of OpenGL2
1b2d22f3 Added logic for OSMesa contexts
e124dd9d Update to the upstream GLEW 1.11.0 release
Merge topic 'DOC_add_information_key_module' into master

25fd4c5f Add a documentation module that contains information keys
Merge topic 'sanitize-bounds' into master

107df717 Added comments about the danger of not clamping.