[datatable-help] v1.6.2 has been submitted to CRAN

[Matthew Dowle]

NEW FEATURES

   o    setkey no longer copies the whole table and should be
        faster for large tables. Each column is reordered by reference
        (in C) using one column of working memory, FR#1006. User
        defined attributes on the original table are now also
        retained (thanks to Thell Fowler for reporting).
        
   o    A new symbol .N is now available to j, containing the
        number of rows in the group. This may be useful when
        the column names are not known in advance, for
        convenience generally, and for efficiency.
        
(The .N feature is needed by package randomNames, now that group
variables are length 1)