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/EditRepositoryNode.cs

@@ -0,0 +1,64 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+using System.Threading.Tasks;
+
+namespace SourceGit.ViewModels
+{
+    public class EditRepositoryNode : Popup
+    {
+        public RepositoryNode Node
+        {
+            get => _node;
+            set => SetProperty(ref _node, value);
+        }
+
+        public string Id
+        {
+            get => _id;
+            set => SetProperty(ref _id, value);
+        }
+
+        [Required(ErrorMessage = "Name is required!")]
+        public string Name
+        {
+            get => _name;
+            set => SetProperty(ref _name, value, true);
+        }
+
+        public int Bookmark
+        {
+            get => _bookmark;
+            set => SetProperty(ref _bookmark, value);
+        }
+
+        public bool IsRepository
+        {
+            get => _isRepository;
+            set => SetProperty(ref _isRepository, value);
+        }
+
+        public EditRepositoryNode(RepositoryNode node)
+        {
+            _node = node;
+            _id = node.Id;
+            _name = node.Name;
+            _isRepository = node.IsRepository;
+            _bookmark = node.Bookmark;
+
+            View = new Views.EditRepositoryNode() { DataContext = this };
+        }
+
+        public override Task<bool> Sure()
+        {
+            _node.Name = _name;
+            _node.Bookmark = _bookmark;
+            return null;
+        }
+
+        private RepositoryNode _node = null;
+        private string _id = string.Empty;
+        private string _name = string.Empty;
+        private bool _isRepository = false;
+        private int _bookmark = 0;
+    }
+}