extension is a file, and so links to TLD's ending with .pl, .au, etc., will
cause accessibility warnings. This fix attempts to distinguish between URI's
that are likely to be files versus links to domains.
- Many, many updates to the public header files.
- tidyenum.h was reorganized substantially in order to better generate
documentation with Doxygen.
- This was also a good time to clean up all of the various enums for languages
and strings. Everything is simple and in a single enum now, other than a
couple of cases (TidyOptionId, for example, doesn't need to be redefined).
- A full and complete audit of the strings meant some opportunities to delete
useless strings.
- Reorganized the order of the strings in language_en.h in order to better
find things when programmers want to make changes. There are a lot fewer
internal "sections" now, and everything has been painstakingly sorted within
the remaining sections.
- Consequently rebased all of the PO's, POT, and other language files.
- Updated several of the READMEs with the newest information.
- Made the READMEs easier to copy into the Doxygen project by changing some of
the code format for compatibility, mainly the use of tildes instead of
backslashes for code blocks.
- Added tidyGetMessageCode() to message API. Despite the huge diff, this is the
only externally-visible change, other than removing some enums (but not their
values!).
- Passing `next` tests on Mac, Linux, Win10.
- tidyDetectedHtmlVersion()
- tidyDetectedXhtml()
- added two new fields to W3C_Doctypes[] in order to simplify this.
- added TY_(HTMLVersionNumberFromCode)() to enable lookup.
- Implement tidyDetectedGenericXml()
- Added a warning message if an XML declaration exists but the document is not
XHTML.
- Remove dead commented code.
- Updated POs and POT. Headers not affected, but translators should check
their translations.
- Testing is clean on Mac OS X, Ubuntu 16.04, and Windows 10.
