For Future Release: Charts of interest

[betterride]

I'd love to see some charts of use to users. Like the following.

1. "Recent" avg MPG for users of a certain car model. Winter driving means decreased performed almost everywhere in the US. It would be nice to know how you rank given that.

2. Avg MPG over time for a certain car model. Takes the idea in #1 and just displays it for all historical time (by month?) Helps owners see trends in vehicle MPG.

3. An update to the existing chart for avg MPG to show the actual avg value of the results shown.