project: reorganize the structure of the project.

* remove dotnet-tool.json because the project does not rely on any dotnet tools.
* remove Directory.Build.props because the solution has only one project.
* move src/SourceGit to src. It's not needed to put all sources into a subfolder of src since there's only one project.

src/ViewModels/DeleteBranch.cs

@@ -0,0 +1,43 @@
+using System.Threading.Tasks;
+
+namespace SourceGit.ViewModels
+{
+    public class DeleteBranch : Popup
+    {
+        public Models.Branch Target
+        {
+            get;
+            private set;
+        }
+
+        public DeleteBranch(Repository repo, Models.Branch branch)
+        {
+            _repo = repo;
+            Target = branch;
+            View = new Views.DeleteBranch() { DataContext = this };
+        }
+
+        public override Task<bool> Sure()
+        {
+            _repo.SetWatcherEnabled(false);
+            ProgressDescription = "Deleting branch...";
+
+            return Task.Run(() =>
+            {
+                if (Target.IsLocal)
+                {
+                    Commands.Branch.Delete(_repo.FullPath, Target.Name);
+                }
+                else
+                {
+                    new Commands.Push(_repo.FullPath, Target.Remote, Target.Name).Exec();
+                }
+
+                CallUIThread(() => _repo.SetWatcherEnabled(true));
+                return true;
+            });
+        }
+
+        private readonly Repository _repo = null;
+    }
+}