Add instructions for installing the application to README.md.

[Korb]

I suggest adding brief instructions for installing the application to the README.md file. Does it require installation, or is the application portable? Does it require specifying the path to the robocopy application? Or do I need to copy the robocopy application file to the folder of this application? Or is it enough to specify the path to the robocopy application folder in Path?..

[Cinchoo]

will do.