Visualization improvement ideas

[mizzao]

Ideas for creating super a badass interactive demo for presentations:

• hover over path to see a player's entire sequence of games
• add animation between default and time-varying display
• integrate zooming functionality (<g transform>) instead of using browser zoom

[mizzao]

Hovering and zooming done in a834156.

We have the per-game time graph so probably no need to put that in the giant sankey. The layout would probably break slightly as discussed in soxofaan/d3-plugin-captain-sankey#8.