Add rtl property in the subrectangle to squarify groups

[stockiNail]

When the groups are computed recursively, the sub rectangle doesn't pass the rtl options but it should.

[kurkle]

Did you encounter this in a use case = do you have a regression test case handy for this?

[stockiNail]

No, I just see that rtl is not passed even if it should be requested. Let me try to create a test case.

[stockiNail]

As you can see, without passing rtl, the sub rectangle are positioned ltr even if I set the rtl: true.

Instead, passing rtl:

I'm adding the test case. Sorry if I didn't do before.