add hypothetical instructions
work around a pynacl bug by manually adding nacl.py to the tarball

The symptom is that 'pip install pynacl-TARBALL' complains about missing
files but claims success, then 'import nacl' fails because nacl.py is
missing. pynacl 'setup.py install' seems to work. nacl.py is
generated (by swig), and I suspect that pip doesn't know quite enough
about swig, and doesn't generate the file. But if it's present it gets
installed.

I'll figure out how to fix this for real later.
trying to make run-from-zipfile work, all broken

Importing pure-python files works fine. I added some half-finished code
into toolbed-app-entry.py; the idea is to find _ed25519.so (and nacl.so,
and any other .so files) and manually load them before giving control to
the main code, since python's importer doesn't know how to dynload from
zipfiles (probably since dlopen() probably requires a real file). It
isn't complete yet.