Allow multiple selection on NSSegmentedControl

[optimisme]

In Cocoa, NSSegmentedControl elements by default only allow one item to be selected, but with 'setTrackingMode':

[bSegmentedAny setTrackingMode:NSSegmentSwitchTrackingSelectAny];

They allow configuring the object to select multiple values. This functionality is necessary, for example, in the selection of text styles (bold, italic, underline, ...) which are multiple On/Off values in the same NSSegment.