Eastern Scheldt (Oosterschelde) is treated as land

Hi Niels,

Just noticed that in the new release the Eastern Scheldt is treated as land in the new [vmstools/data/europa.RData](https://github.com/nielshintzen/vmstools/blob/master/vmstools/data/europa.RData) file. Is this intentional, or is there an alternative map that better distinguishes between land and marine waters?

Cheers,

Pepijn