Merge pull request #873 from DustinCampbell/fix-unity

Ensure that the MSBuild project system adds projects with the .csproj extension, even if they have a different GUID

src/OmniSharp.MSBuild/MSBuildProjectSystem.cs

@@ -160,7 +160,8 @@ private IEnumerable<string> GetProjectPathsFromSolution(string solutionFilePath)
                     continue;
                 }
 
-                if (project.Kind == ProjectKind.CSharpProject)
+                if (project.Kind == ProjectKind.CSharpProject ||
+                    string.Equals(Path.GetExtension(projectFilePath), ".csproj", StringComparison.OrdinalIgnoreCase))
                 {
                     result.Add(projectFilePath);
                 }