Added NVIDIA tls path to LD_LIBRARY_PATH

This fixes a compile error on a Fedora machine.
Bumped up version number.
Added two Python macros
Added copying of Python scripts in the Macros directory.
Added a step in the instructions.

On Mac OS, you need to open the Python Shell first. Otherwise,
a lonely text box pops up with no indication of what to put in it.
Bumped up to Python version 2.6 on Mac (was 2.5).
Added .gitignore file.
Added XML for boolean operation plugin.
Fixed name of BooleanOperation filter and added it to the list of required plugins.
Fixed race condition in Gaussian scalar splatter

The method with the signature

double * vtkDataSet::GetPoint(vtkIdType pointID);

returns a pointer to a member inside vtkDataSet that stores the point
location. When multiple threads access this method, each thread
updates that member variable, leading to a race condition.

Switched to using the thread-safe method

void vtkDataSet::GetPoint(vtkIdType pointID, double * point);

where each thread allocates its own memory to store the point
location.
Resolved race condition in reference counting

Within each thread, a vtkPointLocator is created and its input
is set to the input for the vtkGaussianScalarSplatter. This caused
frequent segmentation faults that I suspect stem from race conditions
in the reference counting increment/decrement operations on the input.

Shallow copying the input works to resolve this issue, but only when
the point locator is not used, i.e., all the points in the input are
processed for all the voxels in the output. This is because there
seems to be another race condition caused by the point locator
modifying some data in the original input despite being passed a
shallow copy of it. Deep copying solves the race condition with the
point locator, but at the cost of copying the data set once for each
thread.

I added a macro called USE_LOCATOR that can be commented out to use
shallow copying or uncommented to use deep copying with the
locator. There is likely an alternative solution that is better than
either of these.
Turned tabs into spaces and made some slight formatting changes.
Fixed odd display of subvolume of 3D Gaussian Scalar Splatter output (BUG 100)

Update extents were not being propagated correctly. Fixed this by adding
an override of the RequestUpdateExtent() method mostly copied over from
vtkFastSplatter. I also had to add an extent translater at the end of
RequestInformation() following the approach used in vtkFastSplatter.

Set spacing in any dimension with one sample to be 1.0.
Initial support for 1 sample in any of the dimensions

The error function (erf) is evaluated only for dimensions that have
more than one sample.

The single plane is positioned at the minimum bound of the input in
that dimension.
Changed the model bounds calculation slightly

For singleton dimensions, the model bounds are calculated to be the
bounds of the input data rather than the bounds of the input data
dilated by the splat width and change.  This means that this filter
can now be used for 2D point input.
Fixed the divisor to normalize properly

For 3D output, the divisor should be 2^3,
for 2D output, it should be 2^2, and so on.
Added note relevant when the point locator is re-enabled

We'll need to project the input points to zero in any
dimension with size 1. Will do in the future if the point
locator is re-enabled.
Made capitalization convention more comformant with VTK
Removed division by voxel volume as it was producing incorrect results
Removed unused variable.