add 3rd party folders back

3rd/libomt/libomt.sln

@@ -0,0 +1,25 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.11.35431.28
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "libomt", "libomt.csproj", "{6D82AB51-3240-46DA-BAEF-F2DD8BB70037}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{6D82AB51-3240-46DA-BAEF-F2DD8BB70037}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{6D82AB51-3240-46DA-BAEF-F2DD8BB70037}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{6D82AB51-3240-46DA-BAEF-F2DD8BB70037}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{6D82AB51-3240-46DA-BAEF-F2DD8BB70037}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {AB7BCB17-6DF5-48E2-B1EE-BA18FCC50869}
+	EndGlobalSection
+EndGlobal