Text shadow

Implemented text shadow to fix issue #1
![dark](https://cloud.githubusercontent.com/assets/7883111/3515332/d81bcfd0-06d4-11e4-80e3-79598b7e4f95.PNG)
![light](https://cloud.githubusercontent.com/assets/7883111/3515334/da2dfd52-06d4-11e4-8da5-1fc3d327d2e2.PNG)