Plugins for add defaultValue features to google closure jsdoc.

i want to use gjslint + jsdoc3.

but gjslint's jsdoc variable type annotations are different with jsdoc3.

especially i want to use "default Value" annotation my project. that's why i make this plugin.

my plugin change below annotations.

```javascript

/**
 * @param {boolean=} useAnother [false] this make blah blah....
 */
function myFunc(useAnother) {
    useAnother = useAnother || false;
}

// replace to

/**
 * @param {boolean} [useAnother=false] this make blah blah....
 */
function myFunc(useAnother) {
    useAnother = useAnother || false;
}
```

finally i make new branch and pull this request.