An 'All' region + Line charts

[zyx]

Also fixed an exception I was getting when running this with empty tables.
Let me know if you'd rather have this split out into individual branches for each feature.

[grosskur]

Wow, this is awesome. Nice work! A couple of thoughts:

• The lines don't always run to the edges of the chart. Rather, they run between the first and last data points in the viewing area. I'm not exactly sure how to fix this. It seems like the chart would need to know about the closest data points off the left and right sides of the window and extend horizontal lines appropriately. It might not be fixable without modifying nvd3 somehow.
• When two lines are following the exact same path, one line "wins" and covers up the other line. I think the graphs in the AWS console draw the lines one pixel apart to avoid this. Neither way is perfect, and again this might not be fixable without modifying nvd3.

Here's an example that demonstrates both: http://localhost:8080/?product=Linux/UNIX%20(Amazon%20VPC)&type=c3.large&region=us-east-1&window=15

Anyway, let me do some more testing... I also want to try with updated d3+nvd3 libraries since the vendored versions are a little old.

[zyx]

Ahh yes, I remember seeing the first problem. One fix might be to just add an extra point at the current time, equal in price to the most recent point, giving you a line all the way up to the right edge. A similar process could be followed on the left side too.

As for the second problem, I can live with it since it's easy to enable/disable individual lines by clicking on their names in the legend, but it would be nice to have some way to distinguish them otherwise.