Fix GRAM size detection under X Window.

The size in kilobytes was saved in an int which was then multiplied by 1024.
With a board equipped with 2GB, this leads to a overflow and an negative
mem size saved in the vtkXGPUInfo structure.
This bug generated issues with some specific usage of
vtkOpenGLVolumeRayCastMapper for instance.

Change-Id: I54af3bb694e12aaa5b32b70a797920fdada3b309
Deprecate the obsolete vtkFastNumericConversion class.

This class was designed as a work-around for some serious performance
problems with the i387 floating-point unit in the x86 family of CPUs.
It is largely irrelevant for modern x86 CPUs which typically use sse
for floating-point computations.  Even though it might give a small
performance boost, it gives an imprecise result.

Change-Id: I65109d827c38bd6dd0ea6ace191885685b6674e3
Cleaned up garbage collection.

Removed garbage collection related Register/UnRegister/
ReportReferences calls from classes that did not need them.
Using garbage collection unnecessarily can lead to
performance issues.

Change-Id: I2eefb6a86d9e64f898247df522a6082c07cec8aa
Improve text shadows.

Blend pixels between character and shadow to prevent gaps where background
color shows between the text and its shadow.

TestScalarBar.png will show the improvement.

Change-Id: I642100a68cae7152d557081d264867d11e79f56a
Document the return value of vtkFieldData::AddArray().

Change-Id: I009d1ad6cce60a1a3b319797c4d6a76206deb2b8
Merge topic 'improve_text_shadows' into master

ce1b4aff Improve text shadows.
Oops. Forgot to remote a print statememt.

Change-Id: Ie7a9f77a495dac728ad9ae595d20ded9a3b10003
Merge topic 'plot3d-improvements' into master

71b73759 Oops. Forgot to remote a print statememt.
Merge topic 'fix_plot3d' into pv-master

71b7375 Oops. Forgot to remote a print statememt.
Merge remote-tracking branch 'pvvtk/pv-master' into HEAD

* pvvtk/pv-master:

Change-Id: If7a78fd5c2c7a76eda1e172bd347f03d1530556a
Merge topic 'forward-to-vtk-master' into pv-master

4cf7ab0 Merge remote-tracking branch 'pvvtk/pv-master' into HEAD
8254f21 Merge topic 'plot3d-improvements' into master
ab2a191 Merge topic 'improve_text_shadows' into master
ce1b4af Improve text shadows.
788dafc Merge topic 'mask_points_can_yield_empty_output' into master
36b6a31 Prevent empty output when input is single-point mesh.
9ae3b4c Merge topic 'AddInteractionsToTests' into master
e7c01b4 Merge topic 'clamp-interpolated-scalars' into master
a06305f Merge remote-tracking branch 'pvvtk/pv-master' into HEAD
74cb04a Fix a memory leak in TestButterflyScalars.
9975ab1 Merge topic 'Fix-HTG-sign-warnings' into master
dceece9 Fix sign/unsigned warnings in HTG.
02d5480 Merge topic 'hardwareselector_warnings' into master
030f293 Fixing warnings in vtkHardwareSelector
f83d821 ENH: Add InteractionStyle to rendering tests
Merge remote-tracking branch 'pvvtk/pv-master' into HEAD

Change-Id: I14227dd1f8d63446d5746dfbe2339fa65a3d7894
Merge topic 'vtkFieldData_AddArray_add_documentation' into master

a7496239 Document the return value of vtkFieldData::AddArray().
Merge topic 'garbage-collection-cleanup' into master

0e39fa5d Cleaned up garbage collection.
Merge topic 'remove-fast-numeric-conversion' into master

3bbd7d2e Deprecate the obsolete vtkFastNumericConversion class.
Merge topic 'fix-GRAMdetection-overflow-under-X' into master

6ac4b149 Fix GRAM size detection under X Window.