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 and then pdf from this docx
everything will work.
Merge pull request #71 from ai-github/master

Fixed several problems converting docx to pdf