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/Commands/QueryRevisionObjects.cs

@@ -0,0 +1,56 @@
+using System.Collections.Generic;
+using System.Text.RegularExpressions;
+
+namespace SourceGit.Commands
+{
+    public partial class QueryRevisionObjects : Command
+    {
+
+        [GeneratedRegex(@"^\d+\s+(\w+)\s+([0-9a-f]+)\s+(.*)$")]
+        private static partial Regex REG_FORMAT();
+        private readonly List<Models.Object> objects = new List<Models.Object>();
+
+        public QueryRevisionObjects(string repo, string sha)
+        {
+            WorkingDirectory = repo;
+            Context = repo;
+            Args = $"ls-tree -r {sha}";
+        }
+
+        public List<Models.Object> Result()
+        {
+            Exec();
+            return objects;
+        }
+
+        protected override void OnReadline(string line)
+        {
+            var match = REG_FORMAT().Match(line);
+            if (!match.Success)
+                return;
+
+            var obj = new Models.Object();
+            obj.SHA = match.Groups[2].Value;
+            obj.Type = Models.ObjectType.Blob;
+            obj.Path = match.Groups[3].Value;
+
+            switch (match.Groups[1].Value)
+            {
+                case "blob":
+                    obj.Type = Models.ObjectType.Blob;
+                    break;
+                case "tree":
+                    obj.Type = Models.ObjectType.Tree;
+                    break;
+                case "tag":
+                    obj.Type = Models.ObjectType.Tag;
+                    break;
+                case "commit":
+                    obj.Type = Models.ObjectType.Commit;
+                    break;
+            }
+
+            objects.Add(obj);
+        }
+    }
+}