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/Makefile

@@ -14,8 +14,12 @@ test:
 	./check_test.sh
 	./deftype_test.sh
 	./escape_test.sh
+	./transform_test.sh
+	./character_test.sh
 	./filename_test.sh
 	./alone_test.sh
+	./state_test.sh
+	./target_test.sh
 	./modulepath_test.sh
 	./klammerset_test.sh
 	./option_set_test.sh