[Dev] repository changes

[Andi Vajda]

I just checked in a bunch of changes related to version merging:

   - The repository format changed, please re-create your repository after your
     next cvs update.

   - Anonymous items are now truly anonymous, their 'itsName' property is no
     longer set to the base64 encoding of their UUID but is now set to None.
     I fixed the repository viewer to display (anonymous) for such items in the
     name column.

     Donn: content items created via 'New' are now truly anonymous

     John, Jed: I made some changes in ControlBlocks.py and
                DynamicControlBlocks.py where a string name was always assumed.

   - Paths to anonymous items now use a new syntax using the base64 encoding of
     their UUID surrounded by {}. For example:
       //CineGuide/{92u1IE1kh7paRo00ejSUdY}

   - Version merging of child collections is partially implemented. You should
     see less VersionConflictErrors with the two hex nums having their 0x0200
     bits set.

Andi..