- explain software and instance separation with eggs

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@32782 20353a03-c40f-0410-a6d1-a30d3c3de9de

buildout/TODO.txt

@@ -26,3 +26,4 @@
  - use declarative way of selecting in-buildout dependencies
      For example mysql-python egg is build against locally built mysql, but
      version of mysql is hardcoded in mysql-python egg part.
+ - have all eggs available as software, but use them selectively in instances