.p-* class names conflict with Microformats

Created by: dissolve

Microformats uses one and two letter prefixings to indicate parsing rules for html.

http://microformats.org/wiki/microformats2

'h-*' for root class names, e.g. 'h-card'
'p-*' for plain (text) properties, e.g. 'p-name'
'u-*' for URL properties, e.g. 'u-photo'
'dt-*' for date/time properties, e.g. 'dt-bday'
'e-*' for embedded markup properties, e.g. 'e-note'.

(also x- for experimental)

Obviously the new p- prefixes clash with this and will distort parsing of any website using the new prefixes. And these prefixes are already quite well established on 10s of thousands of sites (they have been using it since 2009)