Feature/support regex pkg

Hi, yatskevich.

I need to support regular expression for package.

if you accept my changes, we could write expandOverride like this.

```js
{
    "name": "overrideRegexBowerConfiguration",
    "version": "0.0.0",
    "dependencies": {
        "bootstrap": "2.2.1",
        "jquery": "2.0.0"
    },
    "exportsOverride": {
        "bootstrap": {
            "js": "js/*.js",
            "scss": "lib/*.scss"
        },
        ".*": {
            "js": "**/*.js",
            "css": "**/*.css"
        }
    }
}
```

if you find any problems in my changes, please tell me.

Thanks.