PoS upgrade section expanded chart "other" category.

[davecgh]

The chart that shows when the PoS upgrade section is expanded should be sure to never show more than 4 vote versions per interval. I would recommend the most recent 3 versions and an "other". Mousing over the "other" bar should show the breakout of versions in the tooltip.

For example, since version 4 is the most recent one on mainnet, that chart would show v2, v3, v4, and other.

[alexlyp]

Hrm so I can probably add the 'other' category relatively easily
But the tooltip breakout is a decently big feature request that we'll have to do later on.