Trac #17301: Simple typos in the word multiply

some typos in several places, including in one import..

URL: http://trac.sagemath.org/17301
Reported by: chapoton
Ticket author(s): Frédéric Chapoton
Reviewer(s): André Apitzsch
Trac #17247: Add a polytope tutorial

A Sage user has been kind enough to write a polytopes tutorial.  Here it
is!

URL: http://trac.sagemath.org/17247
Reported by: kcrisman
Ticket author(s): sarah-marie belcastro, Karl-Dieter Crisman
Reviewer(s): Karl-Dieter Crisman, Frédéric Chapoton