Add space between content and page number.
Extended PDFTest.
Set margins of PDF documents.
Changed y-coordinate of page numbers.
Changed comment
Deleted unused methods of PDFHandler (they got deprecated by issue#444
and are removed completely now)
PDF Class material list's header content is aligned centrally now.
Added padding to
	- PDF Class material list's header
	- PDF Student material list's header
Removed comment
Merge pull request #576 from B3nRa/pagebreak_issue#575

Pagebreak issue#575