Also do some minor tidying of existing tests and add a missing polarization correction test.

Re #27826

Expose the background subtraction options in ReflectometryISISLoadAndProcess in the ISIS Reflectometry interface. The background processing instructions need to be specified on a per-angle basis so these are added to the Per-Angle Defaults table. The other options can be specified as defaults for all runs so are added as their own widgets on the Experiment Settings tab.

Re #27826

Add feature where an externally generated attenuation profile can be loaded into
the material definition from a .DAT text file. This will override the normal
exp(-alpha*thickness) calculation of the attenuation. The new feature was requested
as part of the absorption calculation for the Pearl instrument where some parts
of the environment are crystalline

Found the lookup\interpolation on the loaded profile was slowing down the absorption
Monte Carlo calculation.
So improved performance of Kernel::Interpolation. Changed it to use vector of pairs
instead of two separate vectors to reduce amount of navigation around vectors

Considered adding feature into AttenuationProfile where I add any interpolated points
into the override attenuation profile to prevent interpolation next iteration of
Monte Carlo simulation. However wasn't convinced this was going to be thread-safe
during the parallel part of the absorption calculation - may revisit this. While doing
this investigation I fixed the following issues with the function Interpolation::AddPoint:

a) it doesn't add the same point twice
b) it reuses the lower_bound function rather than stepping through the vector sequentially

I removed the exception from findIndexOfNextLargerValue because the end()
iterator is a valid result if the x value supplied equals the last x value
already in the vector. Could have left check in for begin() but didn't seem
much point

Finally - the interpolation outside the range is not v good. The data at the extremes
is noisy so we end up extrapolating based on random gradient in extreme 2 points. Need
to either fit or use more points to determine gradient

Also updated class_maker.py

Mac-only eol characters confuse our checksum calculator
and causes the IDF to be downloaded even when this is not
necessary and the downloaded content matches the installed
content

The format of the sample environment xml file has been extended to support
loading a .stl file for each environment component. An example spec file
has been created in ISIS/Pearl.xml. This can be used when running the
Algorithm SetSample
Various SampleEnvironmentXXX units have been moved out the Geometry package
into the DataHandling package to facilitate this because they needed to
access the STL loading code in DataHandling
SetSample contains some features for overriding the sample geometry if the
geometry is a CSGObject. This has been sidestepped for mesh geometries.
The methods setId and setMaterial have been moved up to IObject because
it's useful to have them applicable to all objects (CSG, mesh)
Some of the repeated code in SetSample, LoadSampleEnvironment (and now
SampleEnvironmentSpecParser) has been centralised in a new class LoadStlFactory
Also changed container logic so that if there's only one container specified
in the env spec file you don't need to specify it in SetSample
Centralise code relating to scaling mesh vertices and handling of units
into the LoadShape class and rename it MeshFileIO now that SaveStl is also
descended from this class
Move repeated code to choose Ascii or binary STL reader into a factory class

minixsv is not Python 3 compatible.
Consolidates all XML validation to single module to reduce
code duplication.
Refs #16578

This was provided by Barry Winn

Almost entire rewrite, simplfy everything. Use the det_trans log value instead of hard coded value. Remove all the cal:: values, the calibration will be set in the IDF. Correct the detector positions relative to the beam (centered on pixel (256, 268) and the calibrated detector gap of 5mm.

Signed-off-by: Jose Borreguero <borreguero@gmail.com>

Signed-off-by: Jose Borreguero <borreguero@gmail.com>

Signed-off-by: Jose Borreguero <borreguero@gmail.com>

Signed-off-by: Jose Borreguero <borreguero@gmail.com>

Signed-off-by: Jose Borreguero <borreguero@gmail.com>

Signed-off-by: Jose Borreguero <borreguero@gmail.com>

IDE cleaned up trailing whitespace throughout the file
automatically

Replaces the old mark-as syntax with the newer
and not deprecated is= syntax to avoid warnings
on loading the IDF.