To allow for a different highest sampling rate than 2*fhigh

 - gstlal_inspiral_pipe and gstlal_svd_bank take as option
--sample-rate
 - the waveforms that are generated with a lower fhigh
are shifted forward such that all waveforms in a given
sub bank have a common amount of early warning
 - this has the effect that the actual fhigh of waveforms
is less than requested in a given sub bank, since the
waveforms are shifted according to the waveform that takes
longest to go from fhigh to ISCO

Signed-off-by: Surabhi Sachdev <surabhi.sachdev@ligo.org>