Add comments while reading the script.
Comment to explain xmlns.
comment sections of main()
Unified structure listing
  to replace structure tree and member lists.
Initial release: basically working, but uncomplete.
TODO:
  - fix latex bug (too deeply nested)
  - implement links
  - adapt css
  - consolidate writing of special description sections
  - automatically generate symbol list
Now with links.
Purge script.
Various fixes.
TODO:
- overcome latex limitation, probably using enumitem.sty
- adapt css to suppress right indentation in nested lists
- deal with enumeration and dimension descriptions
Use escaped whitespace to make units=... work.
Various fixes; doc line printing through special routines.
nxdlformat.xsl no longer needed
Improved enumeration printing:
When there are no comments, the allowed values are printed in one line: a | b.
When there are comments, they are printed in separate lines:
  a : comment_on_a
  b : comment_on_b
Symbols printed halfway decently (not as refined as enumerations); no errors;
no warnings except the legacy one.
Small corrections, also of a non-standard entry in NXcite.
New reference format basically complete.
LaTex nested lists issue solved by including enumitem.sty.
Merge branch 'master' into unified-structure-listing
Description of outdated enumeration: more compact and without special formatting.
Enumeration values were enumerated twice.
Remove comments that duplicate keywords given in the <dim> clause just below.
This kind of redundancy does no good, and is a potential source of confusion and inconsistency.
No blank line in <!-- ... -->