Merge branch 'master' into quadtree-test

diff --cc Makefile
Simple merge

diff --cc main.c
index cb8e3fbc1b9a6ad66b3e84c1695d42ca6e1b53f4,c383af71e05f7fe7ad52c059000d0c4a3cd20e62..3349b49708697389469f3416d9157fe244805653
--- 1/main.c
--- 2/main.c
+++ b/main.c
@@@ -193,9 -191,8 +193,9 @@@ static void loop(SDL_Surface *screen, i
        int last_framecount = 0, last_step_count = 0;
        unsigned long old_ticks, ticks = 0, last_frame_tick = 0;
        unsigned long step_count = 0;
-       double last_fps = 0, last_sps = 0;
+       double last_fps = 0, last_sps = 0, fade_amount;
        double step_time = 0, true_time = 0;
 +      int visible_planets;
  
        init_camera(&camera);