[refactor] switch area chart at top of stats page to use Plottable
fix bug where window resize inappropriately resizes all svgs
[feat] Show 7-day moving average of data, update chart title appropriately
[fix] Remove padding on the xScale
[fix] Give legend its own space on top, ensuring it never overlaps data
[refactor] clean out unused css
[feat] Add NPM install data as a red line, with its own axis
[feat] Add axis labels to differentiate now that there are 2 axes
[minor] Upgrade Plottable to get a quick fix for legend behavior (v0.23.2)
[minor] Align legend to left as in original site
[minor] Code alignment ;)
server - enforce users model GA query & npm query have same date range
Address most of Ray's comments:

- Go to bracket/paren free style for parseArray
- put movingAverage into the right closure
- let backend manage date alignment problems
- tick formatting / general axis cleanup
- import plottable.css into b-app.less
- modify gulpfile to minifiy plottable
- increase npm install line thickness to 4px
Move legend to top-left of center plot
Merge pull request #17 from danmane/master

Redo activity / installs chart in Plottable