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/ai/ai_scanner.cpp

@@ -31,6 +31,8 @@ void AIScannerInfo::Initialize()
 {
 	ScriptScanner::Initialize("AIScanner");
 
+	ScriptAllocatorScope alloc_scope(this->engine);
+
 	/* Create the dummy AI */
 	free(this->main_script);
 	this->main_script = stredup("%_dummy");