Various cleanups, bug fixes and a relatively rework of PrismParameterHandler

In 6c72ec4 PrismParameterHandler is now more flexible yet easier to use, especially when using the default implementation SimplePrismParameterHandler.

cbcbffc fixes an issue where the min and max vector would be overridden if the player location wasn't set in the query. Now it checks if min and max are already set.

9b3faf2 is the load of cleanups