Change default opacity and window for secondary series.
Change default opacity and window for secondary series.

The previous values were specifically for use with CT, but a secondary
MR is now the more common case.  Also, remove the "Load Secondary" option
from the menu, since there is now a button for it in the first stage.
Finally, change the radius of the sphere to 2 mm.

Atamai/tactics,Atamai/tactics