settle on "include-site-packages" and migrate all variations of "add-site-packages" to that spelling.

this is now the branch for my site-packages changes.  It is merged with trunk.  The zc.recipe.egg recipe returns to being fully backward compatible; if you want to use a system Python, use the z3c.recipe.scripts recipe for scripts and interpreter.

the whitespace-police, the typo-police, the grammar police, and the Windows testing police all joined together for this check-in of mostly trivial changes.

merge of gary-2-bootstrap-changes into trunk, resolving lots of conflicts with the distribute changes.

Need to check if tests are complete/sufficient, and test with multiple Pythons
and on Windows.

Changed zc.recipe.egg and the easy_install.scripts function into only adding
-S to scripts.

New package z3c.recipe.scripts and the easy_install.generate_scripts now
contains the more robust interpreter generation and the ability to
include site-packages.

Pertinent tests from the previous approach (from 3+ months ago) are
ported.  In the course of this port I discovered that big changes like
the ones in this checkin were needed.