Added sepia filter for simplecv-js

![jen](https://f.cloud.github.com/assets/3799830/452151/4aea6982-b2d4-11e2-8c8f-cdf29cef1d3f.jpg)
![jensepia](https://f.cloud.github.com/assets/3799830/452152/51cbdfb0-b2d4-11e2-8ffe-188e757f4156.png)
![mona](https://f.cloud.github.com/assets/3799830/452153/619726f2-b2d4-11e2-96ee-9d05c1cd578c.jpg)
![monasepia](https://f.cloud.github.com/assets/3799830/452154/6bdf0706-b2d4-11e2-9b8c-b89583017574.png)
![2](https://f.cloud.github.com/assets/3799830/452155/80b38d14-b2d4-11e2-9b09-2aa81610663c.jpg)
![jacksepia](https://f.cloud.github.com/assets/3799830/452156/890e5840-b2d4-11e2-9d93-9330b4035649.png)
![l](https://f.cloud.github.com/assets/3799830/452159/9bddeea4-b2d4-11e2-9c87-36c0c2049f4a.png)
![sepial](https://f.cloud.github.com/assets/3799830/452160/a52f2aa4-b2d4-11e2-977a-c593e9846cfe.png)
![ti](https://f.cloud.github.com/assets/3799830/452161/b8915bee-b2d4-11e2-8858-c2da8d1991e7.jpg)
![tisepia](https://f.cloud.github.com/assets/3799830/452163/bf580090-b2d4-11e2-920d-c341345ef55d.png)