require jsdoc comment style when ignoring Closure constructs

Currently when tolerating Closure constructs JSLint checks for presence of any comments rather than requiring jsdoc. This leads to ignoring, for example, missing function calls if the closure option is activated like the following demonstrates:

```javascript
/*global some_external_function */
/*jslint closure: true */

// Here we must call 
some_external_function;
```

The patch fixes that and require that at least one of the preceding comments must have /**jsdoc*/ style.  The patch assumes that it is OK to use Array.prototype.some.