Adds warning if data rate < 95% in load()

import toolbox_scs as tb

proposal = 5836
runNB =  302
from extra_data import by_index
run, data = tb.load(proposal, runNB, ['PP800_DelayLine', 'BAM1932S', 'FastADC5raw', 'SCS_SA3'])

run, data = tb.load(proposal, runNB, ['PP800_DelayLine', 'BAM1932S', 'FastADC5raw', 'SCS_SA3'],
                   subset=by_index[0::4])

proposal = 2953
runNB =  511

run, data = tb.load(proposal, runNB, ['hRIXS_det', 'hRIXS_delay'])