Implement table caption numbering with a format
"Table 1: <caption>".
Translations are enabled and numbering is consecutive for
captioned tables, uncaptioned tables are not enumerated.
Captioned figures are now also numbered consecutively
and uncaptioned figures are not enumerated.
This changes the way styles for cells in the header row
and normal rows are handled in ODT tables.
Previously a new (but identical) style was generated for
every table, specifying the style of the cells within the table.
After this change there are two style definitions for table cells,
one for the cells in the header row, one for all other cells.
This doesn't change the actual styles, but makes post-processing
changes to the table styles much simpler as it is no longer
necessary to introduce new styles for header rows and there are
now only two styles where there was previously one per table.
