Don`t use references to JsEngine to avoid use-after-free errors,switch to shared_ptr instead

shell/src/Main.cpp

 #include <AdblockPlus.h>
 #include <iostream>
 #include <sstream>
 
 #include "GcCommand.h"
 #include "HelpCommand.h"
 #include "FiltersCommand.h"
 #include "SubscriptionsCommand.h"
 #include "MatchesCommand.h"
 
@@ skipping 22 matching lines @@
   }
 }
 
 int main()
 {
   try
   {
     AdblockPlus::AppInfo appInfo;
     appInfo.version = "1.0";
     appInfo.name = "Adblock Plus Shell";
-    AdblockPlus::JsEngine jsEngine(appInfo);
+    AdblockPlus::JsEnginePtr jsEngine(AdblockPlus::JsEngine::New(appInfo));
     AdblockPlus::FilterEngine filterEngine(jsEngine);
 
     CommandMap commands;
     Add(commands, new GcCommand(jsEngine));
     Add(commands, new HelpCommand(commands));
     Add(commands, new FiltersCommand(filterEngine));
     Add(commands, new SubscriptionsCommand(filterEngine));
     Add(commands, new MatchesCommand(filterEngine));
 
     std::string commandLine;
@@ skipping 15 matching lines @@
         std::cout << error.what() << std::endl;
       }
     }
   }
   catch (const std::exception& e)
   {
     std::cerr << "Exception: " << e.what() << std::endl;
   }
   return 0;
 }