Extended Gruntfile to support features of 0.9.5

- `build/phaser-fx.js` is created from the sources in the `SpecialFX` folder
- generation of `phaser.amd.js` refactored
- added generation of `phaser-fx.amd.js`
- enabled generation of TypeScript declaration files
- enabled keeping the comments in the JavaScript output
- corrected some whitespace ugliness introduced in an earlier pull request