* when try to stash all the local changes, add a option to only stash the staged changes
* stash changes in selected files will prompt user - both staged and unstaged changes of selected file(s) will be stashed
* 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.
