add demo.sln file

demo.sln

+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 15
+VisualStudioVersion = 15.0.28307.421
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "demo", "demo\demo.csproj", "{AEE3F055-5AB8-451A-9F32-51F9C0D35AB3}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{AEE3F055-5AB8-451A-9F32-51F9C0D35AB3}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{AEE3F055-5AB8-451A-9F32-51F9C0D35AB3}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{AEE3F055-5AB8-451A-9F32-51F9C0D35AB3}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{AEE3F055-5AB8-451A-9F32-51F9C0D35AB3}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {67E339D8-AD4B-4C41-A1D3-6E84841068D7}
+	EndGlobalSection
+EndGlobal