Modified SART to take into account the length of the intersection between a ray and the volume of reconstruction
in the weighting of the difference projections.

Modified the -t option in SART to display the execution time of each subfilter at each iteration (very verbose)
Modified rtkConstantImageSource to handle non-zero Index images. Modified rtkSARTConeBeamReconstructionFilter to measure the execution time of each filter over all iterations.
Removed the m_DisplayExecutionTime variable everywhere in rtkSARTConeBeamReconstructionFilter
Added option --positivity in rtksart
Added comment on origin / scale order
Added origin option to rtkDrawSheppLoganFilter
FOV radius was inaccurate because tangent was not taken, fixed.
Added missing input image to interpolator
Added test for floating point lookup tables
Fixed failing tests
Replaced the rtkJosephBackProjectionImageFilter
At the moment, it crashes.
Added support for other GCCs
Warnings: remove obsolete doxygen parameters
Added missing initialization of origin offset
Avoid redefinition of DD and add information when catching exception
Wrong output was written
Replaced the old Joseph back projection filter with one based on
functors, which is the adjoint of the Joseph forward projection filter
Modified a comment in Joseph Forward projection filter
Wrote a test to check that both operators are the adjoint of one another
Merge remote-tracking branch 'remotes/origin/SART_RayBox_TimeProbe_Positivity' into SARTandJoseph
Found the bug in SART. The extractFilterRayBox should be placed before
and not after the RayBoxFilter
BUG: added missing initialization of projection parameters