Switched to new version of udt, kept old version just in case

udt:
- our version, 4.10, was last modified in 2011, the latest version has
way more downloads, and is compatible with the documentation for UDT4 on
sourceforge. For example, many error codes were missing in 4.10 that
were listed in the docs.  I'm not sure what the total changes are, as it
just says "mostly bug fixes since last version".  Whee.