UTF8 coding utilities and unicode escaping in jv_dump()'d strings.

Beyond the Basic Multilingual Plane, dead Cthulhu waits dreaming.

c/jv_unicode.h

@@ -1,5 +1,9 @@
 #ifndef JV_UNICODE_H
 #define JV_UNICODE_H
+
+const char* jvp_utf8_next(const char* in, const char* end, int* codepoint);
+
+
 int jvp_utf8_decode_length(char startchar);
 
 int jvp_utf8_encode_length(int codepoint);