TM v2.12 XML DTD Changes

1. Changed authent, back, da2028, graphic, and icon-set 'boardno' attribute from CDATA to ENTITY and removed the attribute 'type' since the non-SGML/XML type is defined in the ENTITY definition. Instructed by LOGSA to implement the change.
2. Need to the maintain the requirement for notation.
3. Removed from notice the element reprod. MIL-STD-40051B had removed the content requirement, but was not removed in the DTD.
4. Removed faultitem, flghtsafe-part, nomen, proc-item, reprod, specialproc, and specinstruc, which are unused elements in the DTD.