Migrate EmuHawk's post-build targets to shell scripts

(because MSBuild's <Copy/> doesn't want to co-operate)
fixes 2bf1dfbd0, but the batch script is empty so build is still technically
broken on Windows

Dist/copy_assets_and_emuhawk_to_output.bat

@@ -0,0 +1 @@
+REM TODO

Dist/copy_assets_and_emuhawk_to_output.sh

@@ -0,0 +1,2 @@
+#!/bin/sh
+cd "$(dirname "$0")/.." && (cp -r Assets/* output; cp src/BizHawk.Client.EmuHawk/bin/*/* output)

src/BizHawk.Client.EmuHawk/BizHawk.Client.EmuHawk.csproj

@@ -5,7 +5,7 @@
 		<ApplicationIcon>images/logo.ico</ApplicationIcon>
 		<ApplicationManifest>app.manifest</ApplicationManifest>
 		<DefineConstants>$(DefineConstants);EXE_PROJECT</DefineConstants>
-		<OutputPath>$(ProjectDir)../../output</OutputPath>
+		<OutputPath>$(ProjectDir)bin</OutputPath>
 		<OutputType>WinExe</OutputType>
 		<TargetFramework>net48</TargetFramework>
 	</PropertyGroup>
@@ -634,10 +634,8 @@
 		<Compile Update="tools/Watch/WatchValueBox.cs" SubType="Component" />
 		<Compile Update="UpdateChecker.cs" SubType="Code" />
 	</ItemGroup>
-	<Target Name="AfterBuild">
-		<ItemGroup>
-			<AssetFiles Include="$(ProjectDir)../../Assets/**/*.*" Exclude="$(ProjectDir)../../Assets/**/.gitempty;$(ProjectDir)../../Assets/**/.gitignore" />
-		</ItemGroup>
-		<Copy SourceFiles="@(AssetFiles)" DestinationFolder="$(OutDir)%(RecursiveDir)" SkipUnchangedFiles="true" />
+	<Target Name="PreBuild" AfterTargets="PreBuildEvent">
+		<Exec Command='"$(ProjectDir)..\..\Dist\copy_assets_and_emuhawk_to_output.bat"' Condition=" '$(OS)' == 'Windows_NT' " />
+		<Exec Command='"$(ProjectDir)../../Dist/copy_assets_and_emuhawk_to_output.sh"' Condition=" '$(OS)' != 'Windows_NT' " />
 	</Target>
 </Project>