This should make it easier to build pgloader with CCL rather than SBCL, all
from the bundle distribution, and also easier to support windows.
In passing, add a new file in the bundle distribution: version.sexp should
contain a CL string containing the pgloader version string.
Using Quicklisp bundle facility it is possible to prepare a
self-contained archive of all the code needed to build pgloader.
Doing that should allow users to easily build pgloader when they are
being a restrictive proxy, and packagers to work from a source tarball
that has a very limited build dependencies.
