setup.py/packaging changes

* we can be an 'all' package instead of an 'any' package, since we're using
  cffi's dlopen() for pangocffi instead of verify()
* we actually have runtime dependencies on pango, pangocairo, and glib
* setup.py should install the man pages as well
* debian packaging should install the man pages
* clean up the man pages to look more "standard"
* get rid of lintian warning about missing man pages
* qtile.desktop references qtile instead of qtile-session, since qtile-session
  is not installed in the debain packages (and may just need to be deleted...)