Fix a few typos.

Changing a few subheaders per Andrew's suggestion.
Inserted some minor text formatting to make sure
"B/California/NHRC0001/2006" doesn't go out of the margins.
eLife wants to know dates of personal communications and it turns out I
did that on Christmas day.

Small question - for source data we can either include raw
post-processed MCMC output (in which case betweenDiversity data are the
largest and occupy over 250MB) or summary values (mean, median, HPDs)?

By the way, all of this is hopefully going up on arXiv and eLife on
Monday (runs that required re-doing should be finished on Sunday).