Array length support

[Chehow]

It would be great to have array length in UI.
Thx for great job!

[tulios]

Related to issues #95 and #3

[stdedos]

Since the ticket is already open, I guess no real reason to pollute with new issues

Is the default false or true?

Could it be that this specific option has a button very much like 'Show Raw' or '(Un)Fold'?
It is nice to see the number of items, up untill you want to "copy" the json.
I guess I could go back to raw, but I don't like that.

Or an "automagic" way to change it on-the-fly when you copy the text 😄