Install : Not straight forward to install on Windows (Git-bash)

- [x] Install should be easy on Windows with standard install of git (which is git-bash) => one liner to copy-paste
- [x] It should not use **make** (which is not shipped with git-bash)
- [x] It should work to update the version (so install on already installed should update the version of git-standup
- [x] Documentation should be updated to relevant changes