Verbatim-safe typography, ^-punctuation quoting, full-range ^UUUU^, polyglot html

Typographic transforms (---, quote pairs, ~) no longer touch verbatim
text: @c/@code/@source_listing content and ^'...'^ spans show exactly the
characters written. "^" before any punctuation character quotes it in
every target (the apostrophe excepted: ^' opens a literal span), with the
new :resolve option on @@@target declaring per-target renderings. The
^UUUU^ code-point form accepts 4-6 hex digits, the full Unicode range.
The html output and transform spellings are polyglot (XML-valid), in
preparation for an EPUB target. New suites: transform_test, character_test
(engine), typography_test (SKS).

(from dev 07ce5ea86a0a)

tst/editor_test.sh

@@ -10,7 +10,7 @@
 # tst/ is the SKS-independent tier, and these suites check that the
 # implementations of Klammertext's structure agree with the canonical
 # formatting conventions AND with each other.  The klammer names that appear
-# in the fixtures (@ol, @table, @document, @code) are seeded configuration of
+# in the fixtures (@ol, @table, @document, @code, @c) are seeded configuration of
 # the editor tools, not SKS dependencies; nothing here runs ktext or loads a
 # klammer set.
 #
@@ -60,7 +60,7 @@ OUT="$(mktemp -d)"
 trap 'rm -rf "$OUT"' EXIT
 
 INDENT_FIXTURES="indent_list indent_document indent_table indent_untouched
-                 indent_defs indent_escapes indent_named_close"
+                 indent_defs indent_escapes indent_named_close indent_literal_c"
 ALIGN_FIXTURES="align_mixed align_empty_cells align_boundary align_colspan
                 align_escapes align_too_wide"