Grouped Line Charts

[alburdette619]

#206 but without PR pollution from other branches and based off current dev

Adds the ability to group line charts together addressing #205. This uses the same data structure as grouping bar charts:

data: [
  { data: [], svg: {} },
  ...
]

I've confirmed that all lines display correctly and that all children can receive touch events.

[JesperLekland]

This looks super promising! I'll make sure to test it thoroughly asap.
How does a decorator know which path it's decorating?

[alburdette619]

The x and y functions return regardless and each data array contains only one set of line data. Other props are passed along with the data. Thus far I haven't needed to specifically know.

[avinashtadavarthy]

@JesperLekland @alburdette619
It has been added into the github project but it hasnt been updated on npm. So any npm downloaded library file comes without the group line and group stacked js files. Please update it on npm.

[Charanor]

How does one use this with xAcceessor and yAccessor props @alburdette619? I can't seem to figure that one out.