Change: Limit memory allocations for each Squirrel instance

This can avoid out-of-memory situations due to single scripts using up the entire address space.
Instead, scripts that go above the maximum are killed.
The maximum is default 1 GB per script, but can be configured by a setting.

src/script/api/script_object.cpp

@@ -38,7 +38,7 @@ static ScriptStorage *GetStorage()
 
 /* static */ ScriptInstance *ScriptObject::ActiveInstance::active = nullptr;
 
-ScriptObject::ActiveInstance::ActiveInstance(ScriptInstance *instance)
+ScriptObject::ActiveInstance::ActiveInstance(ScriptInstance *instance) : alc_scope(instance->engine)
 {
 	this->last_active = ScriptObject::ActiveInstance::active;
 	ScriptObject::ActiveInstance::active = instance;

src/script/api/script_object.hpp

@@ -18,6 +18,7 @@
 
 #include "script_types.hpp"
 #include "../script_suspend.hpp"
+#include "../squirrel.hpp"
 
 /**
  * The callback function for Mode-classes.
@@ -48,6 +49,7 @@ protected:
 		~ActiveInstance();
 	private:
 		ScriptInstance *last_active;    ///< The active instance before we go instantiated.
+		ScriptAllocatorScope alc_scope; ///< Keep the correct allocator for the script instance activated
 
 		static ScriptInstance *active;  ///< The global current active instance.
 	};