Added emboss filter for simplecv-js

![jen](https://f.cloud.github.com/assets/3799830/456033/833b5c82-b361-11e2-88e6-9d24daec97eb.jpg)
![jenemboss](https://f.cloud.github.com/assets/3799830/456035/9148993e-b361-11e2-9220-1069e0fec8d3.png)
![l](https://f.cloud.github.com/assets/3799830/456039/a424d414-b361-11e2-83f8-61b8d98ef137.png)
![lemboss](https://f.cloud.github.com/assets/3799830/456040/b1cad49c-b361-11e2-8ef2-20e7cc5c14dd.png)
![bike](https://f.cloud.github.com/assets/3799830/456044/cc4e2918-b361-11e2-8d33-e2911b4991a8.jpg)
![bikeemboss](https://f.cloud.github.com/assets/3799830/456046/da6378b4-b361-11e2-8cfb-8b7f7d0b6a89.png)
![cam](https://f.cloud.github.com/assets/3799830/456049/f229f4c8-b361-11e2-9bbf-f21c6639f1dc.jpg)
![camemboss](https://f.cloud.github.com/assets/3799830/456051/f9cdddfc-b361-11e2-9f7c-b7b19b352772.png)