XML decoder additions (#1239)

* Add xml-keep-namespace and xml-raw-token features

* Add tests

* Change flags usage strings

* Append docs

cmd/constant.go

@@ -11,6 +11,8 @@ var inputFormat = "yaml"
 var xmlAttributePrefix = "+"
 var xmlContentName = "+content"
 var xmlStrictMode = false
+var xmlKeepNamespace = false
+var xmlUseRawToken = false
 
 var exitStatus = false
 var forceColor = false