Preserve self-closing tags as is

[suntong]

Following up with #7

goxpath ... reads and writes XML as it wasn't meant for changing the tree.

I found that goxpath.Marshal will change the self-closing tags like <test /> into a pair <test></test>.

Is there any way I can preserve self-closing tags as is?

In a typical jmx file, there are lots of <hashTree /> nodes (or <collectionProp name="HeaderManager.headers"/> etc), and I want to preserve them as-is, after processed/output by goxpath.

Thanks