Installation: create directory first and make ipython optional

...since iocaml no longer requires ipython to be installed at all (!)

Author: avsm

Makefile

@@ -184,8 +184,10 @@ static/services/kernels/js/kernel$(EXT).js: kernel.js iocaml.js
 # install (not needed anymore with iocamlserver)
 
 install:
-	cp -r static `ipython locate profile iocamljs`
+	rm -rf `opam config var share`/iocamljs-kernel
+	mkdir -p `opam config var share`/iocamljs-kernel/profile
 	cp -r static `opam config var share`/iocamljs-kernel/profile
+	-which ipython >/dev/null 2>&1 && cp -r static `ipython locate profile iocamljs`
 
 clean::
 	- rm -f *.cm[io] iocaml_full.byte iocaml.byte iocaml.js