Add pakchois-0.4. (upcoming new neon can use it)

Add pakchois-0.4. (upcoming new neon can use it)
--

pakchois is just another PKCS#11 wrapper library.  pakchois aims to
provide a thin wrapper over the PKCS#11 interface.

The goals are:

1) to offer a modern* object-oriented C interface wrapper for PKCS#11.

2) to not hide or abstract away any details of the PKCS#11 interface
itself except where absolutely necessary.

3) to handle the details of loading DSOs

4) to allow the caller to avoid caring about where on the system
PKCS#11 modules might be stored, or exactly how they are named.

5) to avoid any dependency on a particular cryptography toolkit.

Existing PKCS#11 wrapper libraries solutions differ in at least one of
the above goals.

*: "modern" being a euphemism for not using process-global state,
having a sane symbol namespace, etc.