[Zpt] A few changes...

[Shane Hathaway]

Looking at the PresentationTemplates source, I have a couple of things
I'd like to fix up if I may...

1) PresentationTemplate.py declares security assertions for a bunch of
methods at once.  This works, but it makes it harder to audit security. 
Splitting up the assertions is easy but will affect a lot of lines at
once and I didn't want to do something that will cause conflicts with
someone's CVS sandbox.  Is anyone making any major changes in this area?

2) Expressions.py has its own restrictedTraverse() and it's actually
*unrestricted*.  I'm guessing the reason is because it was denying
access to something, but I think I spotted the real problem: it tries to
traverse the first element of the path.  unrestrictedTraverse() should
only be used with the second element of the path expression.

Shane