Calendar interface to view all history

Have gotten lots of complaints that Better History does not let you view ALL your history. Adding a calendar that lets you view any week's history. 

![screen shot 2014-03-13 at 6 32 11 pm](https://f.cloud.github.com/assets/9306/2416565/c44f54c8-ab07-11e3-901f-dcfe6662b826.png)