Improve serialiser handling of attributes

[ghost]

Close #41

• Add attributes to rendered tags that are missing them

[ghost]

I'm thinking the DOM handler is easier to serialise. It would also permit other XML types to be serialised appropriately.

EDIT: In fact, the DOM handler also doesn't rearrange text nodes interwoven with XML children, making it much less destructive

[manoelcampos]

Hello @lmn8
Sorry for the late reply, but I'm really busy these days.
Are you planning to fix the other items?
Because those would be new issues.

If you are done already, I'll try the code for merging.
I checked quickly and seems to be OK.

Thanks for contributing.

[ghost]

You can merge it. The other issues (CDATA, text node rendering) are going to require handler changes too, so you would need to bump the version.

At some point, I can open a pull that will allow serialising DOM handler roots.