update to latest HEAD.
    
    - Workaround anaconda passing None as group name. BZ 959710.
    - Fix second part of igrp as grp problems. BZ 955236.
    - Add a fuzzy matcher for numbers in format_missing_requires. BZ 718245.
    - Hide the "downloadonly" option when nothing to download.
    - Add the "minrate" option. BZ 964298