#19 Table display - fix center bug

[zlorf]

I noticed that tables are not centered correctly: they were moved slightly to the left.

FIX:
html2fpdfd.php, function _tableWrite, line about 2822.
WERE:
$right = $this->pgwidth - $this->rMargin;
SHOULD BE:
$right = $this->fw - $this->rMargin;

Because right margin has already been substracted from pgwidth, $right behaves as if it had double margin.