Fixed several problems converting docx to pdf

Fixes:
- removed treeCopy from AbstractHyperlinkWriter.java to prevent double
links creation;
- added creation of TblPr to prevent NPE and moving of P created for
<caption> tag in nestedTableHierarchyFix() method in XHTMLimporter.java.

So if one generates docx from html with table that has "caption" tag and then generates pdf from this docx,
everything will work.