Add function get_screen_geometry
It helps handling multiple monitor configuration (with a notebook connected to external monitors)
By testing the size of the screen, we can try to detect the configuration (notebook screen only, or dual monitor configuration), and then decide the placement of the windows

Example :

screen_width,screen_height = get_screen_geometry()
debug_print("Screen width  : " ..  screen_width)
debug_print("Screen height : " ..  screen_height)

second_screen_offset = 0
second_screen        = 0

if screen_width > 1680 then
   second_screen_offset = screen_width / 2;
   second_screen        = 1;
end

if (get_application_name()=="Firefox") then
   debug_print("Firefox detected ")
   -- x,y, xsize, ysize
   if second_screen == 1  then
      debug_print("Second screen detected : ")
      set_window_geometry(second_screen_offset,0,900,700); -- we don't really care about the X/Y size because we call maximize next
      maximize();
   else
      maximize();
   end
end
Cleanup src/script.c (registering of c_set_window_type was done twice - copy/paste error)
Merge branch 'master' of git://github.com/rbarzic/devilspie2 into rbarzic-master