add option for making a T1 cut

[lpgaff]

New option in reaction file to apply a T1 cut to the data.

# T1 cut
#T1.Cut: false			# set to true to enable gating on the T1 time
#T1.Min: 0.0			# [ns] lower limit of event time with respect to T1 time for cut
#T1.Max: 1.2e9			# [ns] upper limit of event time with respect to T1 time for cut