[jdom-interest] Text class in the api

[Bradley S. Huffman]

> If you want to send me your source, I'll run it against the test suite and
> see what has blown up.  First of all, did you base it on the very latest cvs
> source?

I only played with it for 30min-1hr. Give me a few days so I can
make sure I didn't do anything stupid and covered all bases.

One thing is I remember a post about not wanting to force anyone to use
Text class if they didn't want to, I however think it should be one
way or the other, either Element.content has only Text or only String for 
textual content, but not both.