1.- Use arrow keys to modify separation between images (that 
feature was present in previous -IRIS GL- version of gdj, 
at <http://ivo.cps.unizar.es/pub/SPDsoft/gdj-04.tar.gz> 

2.- Implement the "-g: Growable, Keep aspect ratio" option. 
It also worked on 0.4, but I don't know how to do that using GLUT. 

3.- Use network sockets to display every eye on a different 
computer. 

