Fixed Pin Count, UE4.21 and .NET Core

In this update, I updated the project to use UE4.21. The USharp plugin hasn't been upgraded yet, but I created several PRs on the official Repository. You'll notice the game is now 200MB, which is around 60MB greater than before. This is because USharp Bowling now uses .NET Core as the runtime, instead of .NET Framework. This runtime has just been implemented in USharp, so there might be some bugs and crashes that I didn't catch when testing. But the benefit of using .NET Core (preview 3.0 version), is that the user shouldn't need the newest version of .NET Framework to be installed on their computer. Also, this opens the opportunity to port to mac and linux in the future. I can also use the mono runtime, but I couldn't find a way to make the included files less than a 300MB increase in my game size. I've also fixed the pin count bug (for the most part, they still freeze if you sweep while they are falling). They now have a chance to stand back up after registering as fallen.

If this new update causes crashing for you, try going into the Game Folder, go into the "NameOfGame/Binaries/Managed" Folder, open up the DotNetRuntime text file, and change "CoreCLR" to "CLR". This'll tell the USharp plugin to use the .NET Framework, instead of .NET Core. Don't set it to "Mono" btw, because I didn't copy over the Mono files, the game won't work properly.