ENH: add reverse kwarg for topo sort
MAINT: use reverse=True for some topological_sort calls
Update overview.rst

Seems that 'of' is needed ...
Merge pull request #1066 from sbellem/patch-1

Update overview.rst
Thanks.
Merge pull request #1056 from argriffing/reverse-topo-sort

ENH: add reverse kwarg for topo sort