* configure.ac:
        * glib/poppler-page.cc:
        * glib/poppler-page.h:
        * glib/poppler-private.h:
        * poppler/CairoOutputDev.cc:
        * poppler/CairoOutputDev.h:
        * poppler/Page.cc:
        * poppler/Page.h:
        * poppler/TextOutputDev.cc:
        * poppler/TextOutputDev.h: Add support for rendering real
        selection (based on text flow).