New implementation for DOMConfiguration.

New implementation for DOMConfiguration.

This API is disgusting. Its not regular, not typesafe, sparsely
implemented and overly specific. I'm implementing the minimum I can
get away with - exactly the same route taken by the RI.

The Parameter stuff feels a little bit like overkill, but it allowed
me to group related chunks of code together and avoid long chains of
equalsIgnoreCase if statements.

This is necessary to implement Document.normalize(), one of the
last remaining APIs in DOMv3.

Also fixing our implementation of Node.normalize() and adding tests
to discover a bug in that code. Previously a document like this:
  "<foo>abc<br>def</foo>"
Would be normalized to this:
  "<foo>abcdef<br></foo>"
Which is a horrible bug! Yuck.

Implementation and tests for Document.normalize() are forthcoming.