no executable mode on text files please
SegmentBySegment python script updated
to work with the proper mask files
all mask files in SegmentBySegment
are now proper mask files
added valid files
should never need to run valid file
(rather modify ndiff config files accordingly)
wrong column used for error data in mask
sum and diff coupling were mixed
in mask file.

Thanks to Reine for noticing!
Merge remote-tracking branch 'github/master'

Improved SegmentBySegment mask files
Fixed a couple of errors found