Added workspace primitive.

  Allow config file to be specified.
  Added utility function which is a good starting point.
  Updated.
  Use luaL_checknumber.

  This ensures our types are correct.
  Use the correct function-name for moving the workspace.
  We use `workspace` not move_to now.

  workspace(3) will set the window to be on workspace 3.
  workspace() will return the current value.
  Correctly handle maximized/fullscreen windows.
  Document `dump.lua`
  Added unmaximize() + unfullscreen()
  Misc fixup.
  Added example for pidgin.
  Added a media-player sample.
  Added window_application.
  Dump the application too, for less chance of a collision.
  Link to the samples.
  Updated comments.
  Added explicit GPL-2 license.
Ignore the generated binary
  Removed debug info since we have `dump.lua`.
Added Debian packaging stubs