Add mg_remove_double_dots(), hide mg_http_upload()

src/str.h

@@ -40,6 +40,7 @@ uint64_t mg_tou64(struct mg_str str);
 size_t mg_lld(char *buf, int64_t val, bool is_signed, bool is_hex);
 double mg_atod(const char *buf, int len, int *numlen);
 size_t mg_dtoa(char *buf, size_t len, double d, int width);
+char *mg_remove_double_dots(char *s);
 
 typedef void (*mg_pc_t)(char, void *);                  // Custom putchar
 typedef size_t (*mg_pm_t)(mg_pc_t, void *, va_list *);  // %M printer