existsSync is deprecated; maybe use statSync in a try catch instead

Instead of 

``` js
fs.existsSync('some/file');
```

this probably ought to be a wrapper around `fs.statSync`

``` js
fileExistsSync('some/file');
// ...
function fileExistsSync(path) {
    try {
        fs.statSync('some/file');
        return true;
    } catch (e) {
        return false;
    }
}
```
