* Makefile.am, configure.ac: Add configuration for qt wrapper.

        * poppler-qt.pc.in:
        * qt/Makefile.am:
        * qt/poppler-document.cc:
        * qt/poppler-page.cc:
        * qt/poppler-private.h:
        * qt/poppler-qt.h:
        * qt/test-poppler-qt.cpp:
        New files.