improve makefile and readme

Makefile

@@ -1,5 +1,6 @@
 
 build:
+	@echo "\n==== COMPILING ====\n"
 	ocamlbuild ftest.native
 
 format:
@@ -9,11 +10,11 @@ edit:
 	code . -n
 
 demo: build
-	echo "\n==== EXECUTING ====\n"
+	@echo "\n==== EXECUTING ====\n"
 	./ftest.native graphs/graph1 1 2 outfile
-	echo "\n==== RESULT ==== (content of outfile) \n"
-	cat outfile
+	@echo "\n==== RESULT ==== (content of outfile) \n"
+	@cat outfile
 
 clean:
-	rm -rf _build/
-	rm ftest.native
+	-rm -rf _build/
+	-rm ftest.native

README.md

@@ -1,7 +1,7 @@
 Base project for Ocaml project on Ford-Fulkerson. This project contains some simple configuration files to facilitate editing Ocaml in VSCode.
 
 To use, you should install the *OCaml* extension in VSCode. Other extensions might work as well but make sure there is only one installed.
-Then open VSCode in the root directory of this repository.
+Then open VSCode in the root directory of this repository (command line: `code path/to/ocaml-maxflow-project`).
 
 Features :
  - full compilation as VSCode build task (Ctrl+Shift+b)
@@ -10,7 +10,12 @@ Features :
  - automatic indentation on file save
 
 
-A makefile also provides basic automation :
- - `make` to compile. This creates an ftest.native executable
+A makefile provides some useful commands:
+ - `make build` to compile. This creates an ftest.native executable
+ - `make demo` to run the `ftest` program with some arguments
  - `make format` to indent the entire project
+ - `make edit` to open the project in VSCode
+ - `make clean` to remove build artifacts
+
+In case of trouble with the VSCode extension (e.g. the project does not build, there are strange mistakes), a common workaround is to (1) close vscode, (2) `make clean`, (3) `make build` and (4) reopen vscode (`make edit`).