Created a.link.xpointer

Replaced multiple defines with refs
Created a.unitdatetype

Replaced two attribute definitions with refs
Tidy
Created a.transliteration

Replaced multiple attribute definitions with refs to a.transliteration
Created a.relatedencoding

Replaced multiple attribute definitions with refs
Created a.parent

Replaced multiple attribute definitions with refs
Created a.datechar and a.certainty

Replaced multiple attribute definitions with refs
Created a.render

Replaced multiple attribute definitions with refs.  Eliminated
av.render.
Removed data.repositorycode

Moved <data type="token"> into attribute definition
Created a.level

Replaced multiple attribute definitions and av.level
Shifted repeated table attributes to defines

Created a.char,, a.charoff, a.colname, a.colsep, and a.rowsep, replaced
multiple attribute definitions for each.
Renamed a.internal.ptr to am.internal.ptr
Added comments
Alphabetized archdesc notes, other tidying
Alphabetized controlaccess elements
Organized blocks
Moved archref and bibref to blocks section
More rearrangement
Added comment
Reorganized attributes section