Fix a crash caused in part by some missing UI calls in FRED2 and in part by subtle object life cycle issues. Depending on whether FRED receives the focus during mission load (which can happen if the autosave dialog appears) it could access props that were in the process of being cleaned up but were still referenced. This isn't specifically a props issue; it could happen to any FSO object stored in a SCP_vector, since the vector can be cleared.
The quick mission init is to prevent a whole bunch of unnecessary and risky processing during a transient loading state, but it has the nice side effect of making mission list loading noticeably faster.
* First draft of prop object type
* Add prop editor dialog in FRED
* prop sexps
* lua table prop support
* lab support
* lua mission access to props
* prop collision support
* use std::optional so the object->instance id is always valid
* allow props to block suns
* minor cleanup and remove arbitrary limit. Still limited to 500 objects.
* Sort props by category
* cleanup
* implement collision hooks
* parse prop flags and further ensure props are inited and closed correctly
* Add Cyborg's multi suggestions
* fix missing header
* add props to empty slots if available
* add multi signature
* fix rebase issues and match collisions to the new multithread style
* appease Clang the Conquerer
* save/parse mission prop classes by name
* Clean up comments and finish TODOs
* fix string errors
* clang wants this to be static now
* address feedback
* address feedback
* Use model num from prop info instead
* merge prop and ship collision group sexps together
* fix rebase bug
* address feedback
* fix name shadowing
* ship heavy submodel
* clang
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Co-authored-by: Asteroth <[email protected]>
Goober5000