Do more of line simplification with integer coordinates (#113)

* Turn off unit, which has bit-rotted

* Instrument line simplification

* Do more work in integer space

* Update tests with simplification done with more integers

* Clean up

* Update changelog

* Eradicate calls to deprecated sprintf()

* Revert "Turn off unit, which has bit-rotted"

This reverts commit 998779313f.

* Fix catch by switching to an unsigned type

jsontool.cpp

@@ -114,7 +114,7 @@ std::string sort_quote(const char *s) {
 	for (size_t i = 0; i < utf32.size(); i++) {
 		if (utf32[i] < 0xD800) {
 			char buf[8];
-			sprintf(buf, "\\u%04lu", utf32[i]);
+			snprintf(buf, sizeof(buf), "\\u%04lu", utf32[i]);
 			ret.append(std::string(buf));
 		} else {
 			unsigned long c = utf32[i];