Hide private helper types like `xsdDateTime`, `nmtokens`, etc
Hide private helper types like `xsdDateTime`, `nmtokens`, etc

It is much nicer for the user to use standard libary types like `time.Time`
instead of `xsdTime`. Ideally, the user should never know these helper
types even exist. With this change, we accept types like `time.Time`, `[]string`,
`[]byte` and convert them on-demand to `xsdTime`, `idrefs`, `hexBinary`, etc.

droyo/go-xml