[swarm/core] Increased default visibs chunk_delay to 2^23.
[swarm/core] Changed external sync pulse from HB to SOWF.

This implies a complete change to the way we do arm syncs. Firstly,
the sync can be done at any time so the DSM sync time is no longer
necessary as is the threaded calls to the sma_walsh sync arming
tbs_plugin. This commit just manually issues syncs by twiddling
the appropriate bits of sync_ctrl.

Along with this comes a hardware change to SWARM: the external HB
supplied has been changed to a pseudo-SOWF (multiple of a complete
Walsh cycle) generated by the DDS computer and transmitted over a
ribbon cable to a TTL buffer connected to the former HB distribution
box.
[swarm] Changed definition of a "valid" baseline.

This now returns True only if both sides of the baseline are the
same chunk, i.e. it's not a cross-chunk correlation. This changes
some of the downstream data processing and generally eliminates a
bug in the multi-chunk configuration.
[swarm/data] For autos the non-inverted sideband is transmitted.

Previously SWARM was sending the LSB to dataCatcher/corrSaver which
happens to be inverted by default. SWARM now correctly sends the USB
and copies the USB to the "LSB" when using sendIntegration.
[swarm/core] Added ADC5g calibration to SwarmMember.setup()

This now adds the adc5g package dependency which is provided by the
sma-wideband/adc_tests repository.