delete mwlib.pp? (pediapress) move to pdf/ocg?

this doesn't seem to be used anywhere

delete?
merge into pdf class?
merge into ocg stuff?

Change-Id: I72372d2621b285ef27acecb9e01a8a7d0998eafb
Merge "delete mwlib.pp? (pediapress) move to pdf/ocg?" into production