Tag grouping should not be case-sensitive

[hungerburg]

Grouping of results by tag makes a difference between "Ausgenommen" and "ausgenommen" -- Any use-cases [no pun intended] where case-sensitivity is of importance? Most often, I suppose, it is of no importance. But what do I know?

[tyrasd]

A typical use case would be to sort results into classes by tag: e.g. road length by highway tag. Here it does makes a difference: highway=residential is not the same as highway=Residential or highway=RESIDENTIAL.