implementation of a datapicker plugin #225

time picker:

![image](https://cloud.githubusercontent.com/assets/62456/4156033/1c462ab6-3470-11e4-89e2-06a10ca922c8.png)

date picker:

![image](https://cloud.githubusercontent.com/assets/62456/4156042/2f300b6a-3470-11e4-9b59-1c0b4429bbc7.png)