Remove mg_time() and mg_usleep()

src/util.h

@@ -20,9 +20,7 @@ int mg_asprintf(char **buf, size_t size, const char *fmt, ...);
 int mg_vasprintf(char **buf, size_t size, const char *fmt, va_list ap);
 int64_t mg_to64(struct mg_str str);
 int mg_check_ip_acl(struct mg_str acl, uint32_t remote_ip);
-double mg_time(void);
 unsigned long mg_millis(void);
-void mg_usleep(unsigned long usecs);
 
 #define mg_htons(x) mg_ntohs(x)
 #define mg_htonl(x) mg_ntohl(x)