[[ Bug 12462 ]] Use screen coords when constraining stack rect during maximize
[[ Bug 12479 ]] Make sure extent related calculations in MCVariableValue all use uint32_t's.
[[ Bug 12404 ]] Ensure window buffers are flushed to screen before attmpting snapshot.
Merge branch 'release-6.6.2'
Update submodules.
Merge branch 'master' into bugfix-12404

Conflicts:
	engine/src/osxsnapshot.mm
	engine/src/stacklst.h
Merge branch 'bugfix-12404' into release-6.6.3
Merge branch 'bugfix-12479' of https://github.com/runrevmark/livecode into bugfix-12479
Merge branch 'bugfix-12479' into release-6.6.3
Merge branch 'bugfix-12462' of https://github.com/runrevian/livecode into bugfix-12462
Merge branch 'bugfix-12462' into release-6.6.3