Use "Unknown" instead of "Other" as the default name of Browser, OS, and Device

[vanquyettran]

I think it is more exact to mark "Unknown" for what we cannot determine. "Other" means we know what is it but it does not exist in our interest list, or we know it does not exist in the list.

For example, the same OS, but one browser provides OS info, the other one does not. Then we will have, say "Windows", and "Other". Here, it seems that we affirm the second one is not "Windows", but actually we just don't know what is it.

Please consider, thank you!