Redvox

* Add `--protocol` option to redvox-cli when making data request. This allows the data client to optionally connect over HTTP (mainly only useful for local testing)

* Add `mach_time_zero` to TimeSyncData class
* Add `best_tri_msg_indices` to TimeSyncData class to identify which tri-message exchange indicated the best latency and offset
* Add validation checks to ensure that there is no change in sample rate or `mach_time_zero` in the analyzed packets
* Add check for change in `mach_time_zero` when identifying gaps

* Add workaround for accessing `mach_time_zero` in incorrectly constructed Android packets

* TriMessageStats will now append empty arrays in a tuple to tri_message_coeffs when the time sync sensor is empty or doesn't exist.
* Functions compute_barometric_height and compute _barometric_height_array take additional optional arguments: surface temperature in K, molar mass of air in kg/mol, acceleration of gravity in m/s2 and the universal gas constant in (kg * m2)/(K * mol * s2)

* Added a migration module that allows users to slowly begin migrating API 900 data towards API 1000. A flag can be set either through the API or by setting an environment variable `ENABLE_MIGRATIONS="1"`. When enabled, all getters for numeric types will return floating point values (the only numeric type in API 1000).

* Added properties: server_acquisition_times, packet_duration and mach_time_zero to `redvox/api900/timesync/api900_timesync.py` to assist with analyzing time sync data