[Dev] Repository view API

[Andi Vajda]

In the latest repository CVS commit, the repository view API was surfaced to
allow finer control of views and their use with threads. The Repository and
RepositoryView classes were documented with epydoc (first pass).

The Chandler transaction model and views were described in some detail at
    http://pukoo.osafoundation.org/wp/index.php?p=11

To be more consistent with the surfacing of the view API the
Item.getRepository() method was renamed to Item.getRepositoryView() and a new
property - itsView - was added to Item to be more consistent with the other
intrinsic Item properties already available. This property is only gettable
and returns Item.getRepositoryView().

I changed all Chandler code calling Item.getRepository() accordingly.

Andi..