fix git clone documentation

README.md

@@ -51,11 +51,17 @@ and unzip which will add the necessary files.
 You will need to checkout SIBR Core. For this use the following commands:
 
 ```bash
-	git clone https://gitlab.inria.fr/sibr/sibr_core.git
+## through HTTPS
+git clone https://gitlab.inria.fr/sibr/sibr_core.git
+## through SSH
+git clone git@gitlab.inria.fr:sibr/sibr_core.git
 ```
 Then clone the soft3d project
 ```bash
-	git clone https://gitlab.inria.fr/sibr/projects/soft3d.git
+## through HTTPS
+git clone https://gitlab.inria.fr/sibr/projects/soft3d.git
+## through SSH
+git clone git@gitlab.inria.fr:sibr/projects/soft3d.git
 ```
 
 ### Configuration