Final visualization polishes

[alexwgraves]

Changes from feedback:

• [x] Outliers on maps – we should be denoting these with a colored stripes

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• [x] Bubble graph: Make State Average a dashed line on both axes with ticks and tooltip

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• [x] Scatter plot (cash bail and race): Make state average line 100% opacity

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• [x] Fix some mobile wonkiness with the graphs

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Code style/DRYness changes:

• Consolidated mobile style into mobile.css
• Added getPercentOffset to helpers since we use the logic in lots of places
• Added an optional parameter to toMoney that lets us use toLocaleString (set useK to false)
• Simplified updateViewBox for ScatterPlot to just update dx and dy values on the svg elements rather than deleting and re-rendering them every time
• Switched a lot of data["key"] accesses to data.key; I think these were my fault lol, can you tell I usually only write python?