Changed graphs for better visual look and data presentation

 - made graph proportions more thin vertically
 - disabled excessive smoothing
 - updated color scheme to GA-like
 - changed vertical ticks to mark weekly periods

![yoast-ga-graphs](https://cloud.githubusercontent.com/assets/737584/5385094/0d236982-80c8-11e4-9d44-33e46e6a642d.png)