Remove usage of InternalFrameList

Remove usage of InternalFrameList which was introduced in commit a329a7b92 when
the internal frame menu items were converted from radio buttons to normal menu
items.
Remove code related to changing the `selected` status of those menu items,
since they no longer display that status.
Remove InternalFrameList and RadioButtonList, since they are no longer used.
Fix some minor whitespace and style stuff in the touched files.
Fixed issue with unselected frames

When a frame was moved to front by the Window menu, it it was not
selected. The fix was also applied for the editor frame on start up.