Added nonzero exit status upon compilation failure

Author: tazle

src/main/java/org/jcoffeescript/Main.java

@@ -37,6 +37,7 @@ public void execute(String[] args, PrintStream out, InputStream in) {
             out.print(new JCoffeeScriptCompiler(options).compile(readSourceFrom(in)));
         } catch (JCoffeeScriptCompileException e) {
             System.err.println(e.getMessage());
+            System.exit(1);
         }
     }