New option to add attributes range levels or at least a 5th range

[thiagoanjo]

I wish we could add new ranges to numbers on attributes, or at least a new 5th range like: poor, average, good, excellent and superb

For instance:
1-5 - poor
6-10 - average
11-13 - good
14-16 - excellent 
17-20 - superb

[Luke Hume]

Reviewed so locked.