Better support for windows (use any-shell-escape)

Windows just doesn't support the $'foo' escaping that you can use on bash-like shells, so everything fails spectacularly when trying to e.g. add a file to index.

I've [forked](https://github.com/boazy/any-shell-escape) the shell-escape module and tried to make it more generic. It supposed to work on both Windows and bash/zsh now, but still not on every POSIX shell (it doesn't work on csh or dash, for instance).