- we now compute generic style (i.e. inside <styles/> tag) only once
at the begenning of the report.
- for each <para/> tag we encounter, we first try use generic style, and
we only make a deepcopy() of the style structre, in the case there is
some style customization directly on the tag
bzr revid: jvo@tinyerp.com-20100514131355-mdv7jpsapib7edm9