[Feature] support contains relation in venn chart

[purpose233]

What problem does this feature solve?

Support chart like this:

What does the proposed API look like?

  data: {
    values: [
      // rest value
      { sets: [], value 6 },

      { sets: ['A'], value: 8 },
      { sets: ['B'], value: 10 },
      { sets: ['C'], value: 12 },
      { sets: ['A', 'B'], value: 4 },
      { sets: ['A', 'C'], value: 4 },
      { sets: ['B', 'C'], value: 4 },
      { sets: ['A', 'B', 'C'], value: 2 }
    ]

[afkdsghk211331]

我想尝试一下

[afkdsghk211331]

VisActor/VUtil#239