Adds a few more (empty) sections to the CCDA template so that it passes
the requirements for every MU2 CCDA sub-type, not just the ones for
Clinical Summaries.

Also adds better support for producing valid CCDAs with empty sections.
Instead of leaving out sections, a valid CCDA should generally
include the section with no entries or with a single, placeholder entry
(depending on whether the section is required) and improves the code for
outputting addresses
A couple of miscellaneous fixes for CCDAs (more accurate XSD, better escaping)