Clean up classic format mix files

This removes all the classic format mix files and converts those that
didn't already have the new TSV format variants to that variant
Use incremental stats calculations

This commit changes the calculation of geometric mean, variance and
standard deviation to use an incremental calculation approach which will
be slightly less accurate but will hopefully avoid an apparent overflow
issue that has been reported
Format seconds with thousands separators
Add hidden --insecure flag to CLI

Adds a hidden --insecure flag to the CLI that can be used to configure
HTTPS communication to be insecure.  This allows testing against systems
using self signed certificates without having to install the certificate
into your key store but prevents detection of SSL problems.