If we're removing Format() we should remove this as well.

remove CStdString url entirely, and have just char url[2048] (no point being too shy about buffer size)

store return from first sprintf (create var "size_t c"?)

c = snprintf(url, sizeof(url), ...)

// add webroot

c += snprintf(url+c, sizeof(url)-c, "%s", m_webRoot.c_str())

// append user format

vsnprintf(url+c, sizeof(url)-c, fmt, va)