libzen cannot parse if-statements without semicolon.

libzen cannot parse if-statements without semicolon.

```
$ cat test/zen/bug003-if-statement-needs-semicolon.green
function f(n) {
    if(n < 3) {
        return 1;
    }
}
```

```
$ java -jar libzen.jar test/zen/bug003-if-statement-needs-semicolon.green

...

function f(n :var) :var{
   ;
}
(error) (test/zen/bug003-if-statement-needs-semicolon.green:5) ; is expected; } is given
```