remove example singularity file

tuto-singularity

-Bootstrap:docker  
-From:ubuntu:latest  
-
-%labels
-MAINTAINER Vanessasaur
-SPECIES Dinosaur
-
-%environment
-RAWR_BASE=/code
-export RAWR_BASE
-
-%runscript
-echo "This gets run when you run the image!" 
-exec /bin/bash /code/rawr.sh "$@"  
-
-%post  
-echo "This section happens once after bootstrap to build the image."  
-mkdir -p /code  
-apt-get install vim  
-echo "RoooAAAAR" >> /code/rawr.sh
-chmod u+x /code/rawr.sh  
\ No newline at end of file