Put OdfCanvas helper attributes "colspan", "rowspan" & "id" into the HTML document's native namespace

Prevents them leaking into the saved ODF files
Merge pull request #226 from kossebau/doNotLeakListAndTableCanvasHelperAttributesIntoFile

Put OdfCanvas helper attributes "colspan", "rowspan" & "id" into the HTML document's native namespace
Use new StepsTranslator mechanism for
computing positions of paragraphs in
DirectParagraphStyler. This fixes
the case where indentation of a paragraph
with direct-styled text at the beginning
would indent the previous paragraph also.