handle simple XML elements correctly in UnknownXMLTags

1.3

fix UnknownXMLTags for simple elements

Correctly handle slice with single member.

UnknownTags() fix

Handle slice with one member correctly.

process both []interface{} and map[string]interface{} mxj.Map values in all cases

process []interface{} values as well as map[string]interface{} values…

… everywhere

Initial release.

1.0

more doc fix up