With many cores, clear tinker & connect core buttons become inaccessible

[towynlin]

The "clear tinker" and "connect a core" buttons need to remain available, even with a long list of cores.

The fix for this would involve constraints or properties in the Cores View Controller scene of the storyboard, which includes a generic View (containing the "clear tinker" and "connect a core" buttons) inside the TableView of CoreCells.

Also, simpler would be moving those buttons above the TableView. I might do that if no one finds a graceful way to keep them at the bottom.