Revert "By default, sort sequences by size in descending order"
Revert "By default, sort sequences by size in descending order"

This reverts commit d3efc53163faec837c49f576c52518406d485fff that
saved sequences from the longest to the shortest for no good reason.

jsenellart-systran/OpenNMT,jsenellart-systran/OpenNMT,jungikim/OpenNMT,jungikim/OpenNMT,da03/OpenNMT,monsieurzhang/OpenNMT,OpenNMT/OpenNMT,da03/OpenNMT,jsenellart/OpenNMT,OpenNMT/OpenNMT,monsieurzhang/OpenNMT,jsenellart/OpenNMT,OpenNMT/OpenNMT,jsenellart-systran/OpenNMT,monsieurzhang/OpenNMT,da03/OpenNMT,jungikim/OpenNMT,jsenellart/OpenNMT