Changes to base

Changes to base:
commit 5edb063688e73ec00fd1f61ac0e8317dd122f44a
Author: Iavor S. Diatchki <iavor.diatchki@gmail.com>
Date:   Sun Mar 23 17:10:38 2014 -0700

    Comments only.

    Fix the documentation on CmpSymbol and CmpNat; add a note on (<=?).