The Third OpenDocument patch - Headers and Footers

Hi guys,

Attached to this e-mail is my third OpenDocument patch. It adds
**initial support to headers and footers**.

It's kinda big because I had to modify the architecture of the plugin
implementation. So there's a lot of code movement from a file to another.

It now implements a State design pattern. I had to do this because the
header/footer parsing shares most of the code used to parse the text
content itself.

Any comments?

The next patch will improve the header/footer support.

Best Regards,
Daniel d'Andrada T. de Carvalho - INdT