macos:  Add empty _Init{Fonts,Windows,Menus} traps
Beep:  Always call InitWindows() and InitMenus()

These are stubs in macos now, so it's safe to call them unconditionally.
Beep:  Add missing InitFonts() call

We're supposed to call this before InitWindows().
v68k-mac:  Add WMgrPort low memory global
macos:  Create new WMgrPort in InitWindows()
macos:  Draw the desktop in InitWindows()

Paint the screen black, exclude the round screen corners from WMgrPort's
clipping region, and fill with gray.
Merge branch 'WMgrPort'