r41Alpha3

[Chris Muller]

I've just posted r41Alpha3 to the "MagmaTester" project of SqueakSource.

Most notable is the inclusion of sig's MaDictionary redesign.  Thanks
Igor!  The test cases pass with them but I haven't done anything more
at this point.  Proceed with caution, just in case.

Also included is a good bug fix for renaming classes.  Magma was being
notified of the rename, but needed to rehash two of its internal
Dictionary's to ensure subsequent access is correct.

There are other minor improvements.