[REQUEST] Category rename and convert case

[mrbentarikau]

The problem currently is when you just want to rename a category, e.g. just to convert case; let's say from space to Space, Depressurizer will not let you do it and gives a warning window: "Name space is already in use".

This interface level fix should be easy because these characters are actually different. Depressurizer should make byte comparison between characters and see that s and S as 0x73 vs 0x53 differ and should allow that category rename.