`QVM` is no longer quicklisp loadable (`clos-encounters` dependency)

[Izaakwltn]

Because of the dependency on clos-encounters, qvm is no longer out-of-the-box-quickloadable.

I don't know if this project cares that much about being quickloadable, but it might be a hindrance to first time users.

There are probably 3 options:

1. Add clos-encounters to quicklisp
2. Roll clos-encounters into the qvm repo
3. Let quicklisp loading be broken but document dependencies well on the README

[stylewarning]

Let's at least do #1.

[Izaakwltn]

Sounds good, I'll do that tomorrow unless someone else wants to

[Izaakwltn]

quicklisp/quicklisp-projects#2407 Looks like a request has already been made, and there seems to be a hefty backlog

[jdriordan]

A quic fix for the meantime:

cd ~/quicklisp/local-projects
git clone https://github.com/quil-lang/clos-encounters.git