- add liblightdm-qt5-3-0 and liblightdm-qt5-3-dev (packaging bits imported
  from Ubuntu)                                                closes: #871840
  - add build-dep on qtbase5-dev
  - move libraries to section libs
  - update standards version to 4.1.0
  - replace dh-systemd build-dep by a newer version of debhelper
* debian/liblightdm-qt5-3-0.install and debian/liblightdm-qt5-3-dev.install
  added to ship relevant files to Qt5 library and development packages
* debian/liblightdm-qt-dev.install:
  - narrow installation path to only cover Qt4 library.
* debian/rules:
  - explicitly enable qt5 library