Add a non-package install instructions

[rusimody]

ATM when I try package-install haskell-mode it finds no such; only finds haskell-emacs

Packages in emacs are sufficiently broken for enough people
Please put the 'old-fashioned' or manual procedure also.

IOW something of the form

1. Put this in load-path
2. Put this in your init
3. You will need this set <... > of packages pre-installed

Update: Install via git worked

[gracjan]

We aren't able to maintain and take responsibility for many ways of installing. Melpa and git is enough.