(install.sh) Symlinks not working if a folder name contains spaces

If there is a space into one folder from the path the symlinks does not work as aspected.

**install.sh (line 11 and line 12)**
`ln -s $PWD/zshrc   $HOME/.zshrc`
`ln -s $PWD/gitconfig $HOME/.gitconfig`

Enclosure the paths does fix these behavior:
`ln -s "$PWD/zshrc" "$HOME/.zshrc"`
`ln -s "$PWD/gitconfig" "$HOME/.gitconfig"`