rather than blanking them out entirely.
This lets csv-to-json.py handle the case where an earlier input file has (e.g.)
a registration value which does not match the computed value, and then a later
input file has a value that does match. In this case we want to override the
older value with the newer value, then notice that the registration can be
omitted when writing the database. Previously in this case the older (incorrect)
value would be used.
* Better preamble detection to skip most of the messages we'll likely
not be able to decode.
* A Phase correction algorithm that improves the recognition compared
to the previous algorithm used.
* Javascript output in debug mode, and a debug.html file that can be
used in order to see graphically undecoded samples.
* Ability to detect cross-read messages, that are, messages that happen
to start and end across two different reads from the device or file.
* A few bugx fixed.
* README improved.
