MDEW rebinning via loaded LoadMDEW

[Owen Arnold]

Now that the MDEW loading can use a file as backend, critical to expose this property.

In addition, the *.nxs type MDEW constitutes a different loading route, so new reader/object panel is required to support this. It is also necessary to differentiate this type of nexus file from the event-nexus type nexus file, so that the correct reader can be identified by PV.

[Owen Arnold]

In [13474]:

Refs #3420. Loading works. File identification works (at least for the types of nexus files available). Timestep iteration works. Users can select to reload the workspace into memory via GUI.

[Owen Arnold]

In [13475]:

Refs #3420. Fix GCC warnings.

[Owen Arnold]

In [13476]:

Refs #3420. Fix outstanding GCC warning.

[Janik Zikovsky]

In [13483]:

Refs #3316 and refs #3420: Made the MDEW .nxs file format closer to the Design Document specification. Lots of bits (sample/run/instrument) are still missing. Adjusted the PV plugins to find the right kind of loader and fail (gracefully) if given a processedNexus or a SNS event Nexus.

Refs #3271: Sped up vtkThresholdingQuadFactory and vtkThresholdingHexahedronFactory furthere.
Time to create voxels sped up by 40x (19 seconds to 0.45 seconds for 100^{3 voxels).
Time to check the signal for thresholding of 500}3 voxels dropped from 19 seconds to 3.4 seconds.
Made vtkThresholdingUnstructuredGridFactory subclass vtkThresholdingHexahedronFactory so that they could share their common code.

[Michael Reuter]

Loaded on a saved MDEW file and all went well.

[Stuart Campbell]

This ticket has been transferred to github issue ​4267