Remember last position in dataset without saving an annotation

[orenshatz]

The user might browse a dataset without actually annotating anything. Nevertheless, upon opening knossos again, he may expect continuing browsing from the same position. It would make little sense for him to save a specific annotation file, whose location he would have to remember next time and point to, just to be able to do that. I suggest saving a dataset position for each dataset. Implementation wise, the position should be coupled to the conf location in the dataset list we already keep.