Fix TDATA segfault

Node is deleted multiple times, causing segfault in vtkMRMLScene::
GetNodesByClass

See: https://github.com/SlicerIGT/OpenIGTLinkRemote/issues/18
Merge pull request #23 from ihnorton/tdata_segfault

Fix TDATA segfault
Implement vtkMRMLIGTLConnectorNode::Persistent

This option represents whether or not a connection should
be persistent across scene saves.

if `persistent == ::PERSISTENT_ON` then the node connects
based on the `::state` setting.

if `persistent == ::PERSISTENT_OFF` then the node does not
reconnect when the scene is loaded.
STYLE: Untabify + VTK-style indentation.
ENH: Updated according to Transforms module API
Merge pull request #25 from lassoan/transform-fixes-3610-3611

ENH: Updated according to Transforms module API
ENH: enabling color image support

Number of components now set from image message.
Display node color table now set depending on number of components.

I'm not sure if there's a clean way of downcasting an igtl::MessageBase into a igtl::ImageMessage so for now I operate on the inner pointer. If anything fails it reverts to the original greyscale image.
ENH: enabling color image support

Number of components now set from image message.
Display node color table now set depending on number of components.
Repariring whitespace
Cleaning up the message base to prevent programmer error and to simplify future development
STYLE: Fix indent style.
ENH: cleaning up build warning and using polymorphism to clean up the calling code
ENH: changing function name to prevent build warning
BUG: Color table ID was not properly set in vtkIGTLToMRMLImage.cxx.
COMP: Fix unused variable warning reported in Slicer Bug tracking 3665 / Github issue #30
Merge pull request #31 from tokjun/3665-unused-variable-warnings

COMP: Fix unused variable warning reported in Slicer Bug tracking 3665 / Github issue #30.
ENH: Support VTK6.

1) Remove deprecated Macro.
The following two macros were deprecated in VTK 5.0 that were still supported, but have now been eliminated:
vtkTypeRevisionMacro has been replaced with vtkTypeMacro; vtkCxxRevisionMacro has been removed.
http://www.visitusers.org/index.php?title=VTK_6.0_Upgrade

2) Replace SetInput() with SetInputData() and SetInputConnection(), the same kind of functions include SetInput1(), SetInput2(), AddInput() and SetSource().
http://www.vtk.org/Wiki/VTK/VTK_6_Migration/Replacement_of_SetInput

3) Change scalars manipulation functions
http://www.vtk.org/Wiki/VTK/VTK_6_Migration/Changes_to_Scalars_Manipulation_Functions.
http://vtk.org/Wiki/VTK/VTK6/Migration/WikiExamples#Improve.

4) Remove Pipeline Update Methods from vtkDataObject.
http://www.vtk.org/Wiki/VTK/VTK_6_Migration/Removal_of_Update.
Conflicts:
	MRML/vtkIGTLToMRMLImage.cxx
ENH: Display 3-component images as true color RGB images. 3-component
image data through OpenIGTLink creates a vector or scalar display node
dependeing on the number of components sent by the source.

Also fixed a crash/partial image update when the number of scalar
components are changed.
Merge branch 'master' of https://github.com/adamrankin/OpenIGTLinkIF