Allow setting compiler options in loader query

To allow users to set compiler options, you can use [loader-utils](https://github.com/webpack/loader-utils) to parse the loader's [query](http://webpack.github.io/docs/loaders.html#query) into an object. They could be specified like this:

``` js
{ test: /\.ts$/, loader: 'ts-loader?target=ES3,module=AMD,-sourceMap' }
```
