File EventSystem.h: Include ship/events/Events.h and use Ship::Events directly.
Class Ship::OtrArchive: OtrArchive and the ".otr" format are deprecated in favour of the ".o2r" format backed by Ship::O2rArchive. MPQ support is disabled by default; opt in with -DINCLUDE_MPQ_SUPPORT=ON only for projects that still need to load legacy ".otr" archives. New projects should use the ".o2r" format exclusively.