Introduction of tag, layers and linearization support in okular

by Saheb Preet Singh for KDE

Okular is a KDE universal document viewer with support for a lot of different formats like PDF, PostScript®, Tiff, CHM, DjVU, Images (png, jpg, etc.) XPS, Open Document (ODT), Fiction Books, Comic Book, Plucker, EPub and Fax. But it currently lacks some of the features currently supported by the poppler ( pdf backend for okular ) such as pdf layers, tagged pdf support and linearized pdf support. This project focus on implementing the missing functionalities.