Show CSets/Types menu options should use radio buttons instead of checkboxes

Only of of these two View menu options can be selected at one time:

Show CSets
Show Types

But the checkmark that appears to the left of them gives the impression that they can be toggled independently. Consider changing the checkmark to a radio button.

There should also probably be a horizontal line between them and Show Walkability/Show Flags as those two are unaffected.