LoadSNSEventNexus: don't create empty pixels when loading only 1 bank.

[Janik Zikovsky]

... add an option for this purpose.

[Janik Zikovsky]

Results from the following script:

import time
file = "/home/8oz/Desktop/topaz.cal"
CreateCalFileByNames("TOP", file, "bank9")

for singleBank in [False, True]:
	print "Starting with SingleBankPixelsOnly",  singleBank
	start = time.time()
	LoadSNSEventNexus(Filename="/home/8oz/data/TOPAZ_1786_event.nxs",OutputWorkspace="TOP",BankName="bank9",Precount="0", SingleBankPixelsOnly=singleBank)
	Sort("TOP")
	AlignDetectors(InputWorkspace="TOP",OutputWorkspace="TOP",CalibrationFile=file)
	DiffractionFocussing(InputWorkspace="TOP",OutputWorkspace="TOP_foc",GroupingFileName=file)
	print time.time() - start, " seconds."

Results:

Starting with SingleBankPixelsOnly False
53.2949681282  seconds.
Starting with SingleBankPixelsOnly True
38.5822250843  seconds.

[Janik Zikovsky]

(In [9408]) Fixes #2393: LoadSNSEventNexus to load only one bank and not pad all the other empty pixels.

[Russell Taylor]

(In [9421]) Catch exceptions thrown out of parallel region. Re #2393.

[Stuart Campbell]

This ticket has been transferred to github issue ​3240