better README

README.md

@@ -12,21 +12,27 @@ Installation:
 
 On Debian, the following packages should be installed first:
 
+```
 sudo apt-get install libwxgtk3.0-dev wx3.0-headers libwxgtk-webview3.0-dev libwxgtk-media3.0-dev
+```
 
 Then, as usually:
 
+```
 ./configure
 make
 make install
+```
 
 Note that normally, examples in `samples/` are compiled as part of
 `make`, but to be sure it is correctly installed, you can do the
 following to build them again after installation:
 
+```
 cd samples
 ocp-build init
 ocp-build
+```
 
 All examples should then be available in the _obuild/ sub-directory.