introducing the persona flag and a definition of a persona in the spec
removing the references from a source to its extracted conclusions because the information is redundant with the  flag.
woops! didn't mean to get rid of 'attribution' documentation on the person...
Adds textType to the Document class.
Modifies the specification to add the concept of __*extracted information*__ to conclusions.
formalizing the notion of 'persona' using the notion of 'extracted information'
s/encloses/contains
providing additional details about the document text types, limiting the required set of XHTML modules
clarifying the required, optional XHTML modules
listing out the specific modules for clarity

listing out the specific modules under each module group for clarity.
s/extracted information/extracted conclusion so as to avoid introducting another concept in the conceptual model that must be defined.
json, xml updates for the 'extracted' flag
Merge branch 'persona-flag'

Conflicts:
	specifications/conceptual-model-specification.md
Merge branch 'document-text-type'