Divide DT search range into 3 segments. Search central segment (near DT=0)
first and try to decode the largest peak. Then find the largest peak in each
of the surrounding segments and try to decode those only if the peak is larger
than the one found in the central segment.
Also re-indent ft4_decode.f90 and some other minor tweaks.
through the analysis window.
Add a random 77-bit vector to each message so that tone transitions occur
even if the message contains a long string of 0 or 1 (like a CQ).
Add alternative sync calculation as an option (sync2), for testing.
Add basic framework for AP decoding.
