Upgrade dosbox solution and project to VS2019

Clean up project settings to prevent most MSVC linker warnings.
This commit also adds MSVC builds to CI.

.github/workflows/build.yml

@@ -88,3 +88,41 @@ jobs:
           make -j "$(sysctl -n hw.physicalcpu)" 2>&1 | tee build.log
       - name: "Summarize warnings"
         run: python3 ./scripts/count-warnings.py build.log
+
+  build_msvc_debug:
+    name: "MSVC 14 Debug (win-2019)"
+    runs-on: windows-2019
+    steps:
+      - uses: actions/checkout@v1
+      - name: "Install packages"
+        shell: pwsh
+        run: |
+          vcpkg install libpng sdl1 sdl1-net
+          vcpkg integrate install
+      - name: "Build"
+        shell: pwsh
+        env:
+          PATH: '${env:PATH};C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\amd64'
+        run: |
+          # build steps
+          cd visualc_net
+          MSBuild -m dosbox.sln -p:Configuration=Debug
+
+  build_msvc_release:
+    name: "MSVC 14 Release (win-2019)"
+    runs-on: windows-2019
+    steps:
+      - uses: actions/checkout@v1
+      - name: "Install packages"
+        shell: pwsh
+        run: |
+          vcpkg install libpng sdl1 sdl1-net
+          vcpkg integrate install
+      - name: "Build"
+        shell: pwsh
+        env:
+          PATH: '${env:PATH};C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\amd64'
+        run: |
+          # build steps
+          cd visualc_net
+          MSBuild -m dosbox.sln -p:Configuration=Release