Subgrouping and sorting

[hefler]

First of all, thanks for this great plugin!

I find the user telling which / defines a group sorta misses a great opportunity. There's a reason designers add a / to the symbols and that is Sketch's "grouping" system. If one has to pick where it shall starts, it kinda defeats the purpose of not considering the other groups.

That said, I'd like to suggest to use the first instance as the whole group, then for every "/" encountered a subgroup is created with spacing for the "deeper" groups being less than the one before. In that way the page will reflect the intended symbols organisation.

Also for each item in a subgroup it should be numerically and alphabetically sorted in the layers and on the page.