Add tooltip with values to bar chart

[briehl]

Mousing over a bar chart could show the values in that bar. Just something like:
total: x
active: y
recovered: z
deaths: a

Should have a translucent background to not cover the chart, or always be positioned away from that bar (maybe off to the side and an arrow pointing at it?)

[jayrbolton]

+1
For a dirty mvp we can just give the divs title attributes, that would do the job

[jayrbolton]

Added the title attributes in #21

Will keep this open for a nicer tooltip. Here's an example with tachyons: https://codepen.io/syndicatefx/pen/QVPbJg. That one is probably overkill, but the basic principle is to use .hide-child

[briehl]

That's pretty nice!