Metop v2 rebase

The metimage read routines for the new proxy data work now. We can merge it into develop branch. Please check if output is okay. Thank you. Andi

This branch was based on a quite old commit of the repo. Naturally, there are merge conflicts. There is also code that got copied into the destination branch.
So I rebased on the v1.0.0 release and removed two commits that had already been incorporated into develop.
- Coda