[DFDL-WG] updated errata on implementation-defined features

Working Group, I finished going through the specification looking for implementation-specific features that should be listed as "implementation-defined". Resulting document attached. The only item I added from the last draft was one for defining the number of fractional second digits supported in dfdl:calendarPattern. Track changes is turned on, so the addition should be apparent. Fyi, -- Jonathan W. Cranford <jcranford@mitre.org> Senior Information Systems Engineer The MITRE Corporation (http://www.mitre.org) 801-903-3431 [cell]