[WIP] Boxplot

[mattwchun]

• Update CompassQL Mark Type and Aggregation Function

• Update default aggregation to enumerate [undefined, #'box-plot'] instead of [undefined, 'mean']

• Add New Constraints

  • only one axis should be continuous( if there is another axis, it should be discrete)
  • aggregate = boxplox iff mark = boxplot

• Update Rankings

[mattwchun]

test cases

• write a query with mark = ? with one Q-field where aggregate = {enum: [undefined, boxplot])

• write a query with mark = ? with one N-field and one Q-field where aggregate = {enum: [undefined, boxplot])

• write a query with mark = ? with two Q-fields where aggregate = {enum: [undefined, boxplot]) -- this one shouldn't show any boxplot because it's dumb

• write a query with mark = ? with two Q-fields where aggregate = {enum: [undefined, boxplot]), bin = {enum: [false, true]) -- the case where one of them is binned would make sense