Meta-Data documentation

Hi,

As promised, I've made a userguide patch that adds meta-data documentation.

I've added appendix G. on Meta-Data (Former Appendix G. on Log Files is now
Appendix H.) and also added references to the new keywords and parameters
where appropiate.

Aside from that, I also fixed all "See section on regular expressions" to
hyperlink to the proper appendix. This is not really related to meta-data
but makes the documentation easier to follow IMHO.

Here's the patch:

http://www.magicom-bcn.net/kannel/userguide-meta-data-cleanup.patch

I've rendered the HTML and PDF on my box and looked ok.

Please let me know if you agree with what I wrote, or if you wish to
add/change/delete anything.

Regards,

Alejandro