An option to enable double character label

[kurtontheway]

52 single character labels are often not enough for a view with full of lines, double character label should help.

[ice9js]

I was hoping the current batching functionality would solve that problem - by allowing you to cycle to sets of results with Enter or any other key you have set up. It's just as convenient and requires just as many if not less key presses.

If you would like to have the option to switch between that and multiple character labels - I'll leave this open for implementation. Unfortunately I can't promise any ETA since I've found myself really busy lately, but feel free to bump this issue every few weeks.

[kurtontheway]

Tried the "batching functionality" for days, and finally, I found some time to implemented "double char labels" - #68