Small tweaks and a small bug related to the witchfight in Deadwell — Northern Journey Steam update #824414

I watched a stream where the streamer fought the witch in Deadwell. She flew too high. I was not able to replicate it, but I changed some parts of the rather old AI logic of hers, so she should be much closer to the ground now. Clarified the onscreen message after pulling the switch in Nokkpond from 'Something opened..' to 'A door opened very close by'. Removed some health from the Trollspawners. They can be killed with two sling/bow shots instead of three. Further reduced the souls required to pass the gate in Sourwood, from 160 to 130. There wasn't really a good reason to have it so high, and some people was annoyed by it.