Improvements to the man page

[snim2]

1. Add in more examples
2. Explain CI levels better. Explain 2/3/5 sigma. Give an opinion as to best practice.

[zbentley]

This would be helpful for myself and my colleagues as well. Additionally, it would also be helpful for commandline options to have clearly documented default values.

[Lewiscowles1986]

As an addendum to this, can I ask if the following can be explained or fixed if it is indeed a typo?

the mean is reported at a 95% confidence level (-c 99).

Surely -c 95 would give 95% confidence level? or you'd need -c 100 as well as -n 100 to have even the slimmest semblance of confidence in n% range?

[ltratt]

The confidence interval code is, as far as I can remember (and @snim2 might know more!) slightly unfinished.