Improve row "trackability" when scrolling

[nilshg]

I currently find it very hard to read wide tables in TableView as I lose my bearing on which row I'm looking at when scrolling. I have two suggestion for improving this:

1. Making the Row colum a fixed column that exists "outside" the table, in the same way the column headers do - I think I originally suggested this when submitting the feature request on the row numbering column, so there might be reasons for not doing this

2. Extend the cell selection frame (the little blue border box around a cell that appears when clicking on a cell) to the whole row - it seems to me like just selecting a single cell to highlight offers few benefits to the user, while selecting a row in that way would allow keeping a row highlighted when scrolling horizontally.

[pdeffebach]

This seems fixed, right?

One other thing, new rows aren't highlighted while scrolling down. Maybe we can make "Enter" highlight the whole row?