Autocorravg: spit out a warning if people try to average over ridiculously large gaps

[mohanagr]

happens if data collection stopped (i.e. reboots, people doing stuff in the field etc.)

specnum overflow fixed in dev, but it'll just continue averaging and those spitting out empty rows because there's no data! and there's no guarantee that specnum on a reboot line up with specnums pre-reboot. It's the user's responsibility to pass correct arguments to the script.

[mohanagr]

I think most of this can be handled by the file finding scripts. Master branch has a shitty globbing solution. dev has a much more robust way to find files.