Log Message:
py-more-itertools: updated to 4.2.0

4.2.0:
* New itertools:
    * :func:map_reduce
    * :func:prepend

* Improvements to existing itertools:
    * :func:bucket now complies with PEP 479

* Other changes:
   * Python 3.7 is now supported
   * Python 3.3 is no longer supported
   * The test suite no longer requires third-party modules to run
   * The API docs now include links to source code