Add capability to process in-fight logging startup

[sco1]

For cases where we forget to turn the logger on before taking off, there should be an ability to begin a flight segment at the start of the file. Since there was an intentional decision to not consider segments at the start of the file (see: #5), this should be an opt-in switch.

While we're at it, the default behavior should fail more gracefully rather than conking out in the segment classifier when attempting to reshape the segment start/end indices.