new queries beta packages

[Chris Muller]

I've posted new versions of individual packages for Magma:

  - improved query correctness and stability, particularly with respect
to local (uncommitted) changes to the underlying MagmaCollection.
  - Merged improvments from Keith Hodges; create: and delete:, which
now permit a local path specification.  Thanks!
  - added MagmaCollection>>#where:distinct:sortBy:descending: and
MagmaCollection>>#where:distinct:sortedBy:descending: convenience
methods.

Thank you to everyone who has been helping test this queries function,
this is turning out to be a great and useful feature.  We're still in
beta, but getting closer, ever closer..  I still need a test cases to
cover changing keys and ensuring the querying and sorting works
correctly among the changed keys.

Please let me know if you find any problems.

Cheers,
  Chris