add missing opt-* files to OPTFILES in Makefile
Makefile scripts to make a tar file for the arXiv

(still getting hyperref option clashes)
Add some missing files to the arXiv tarball
fixed erroneously bound path p in proof that PI implies based PI
updated errata with change
Clarifying remarks about whiskering and Eckmann-Hilton

close #415, close #413.
errata for a1c62da, unmarked
The "fibers" of the Hopf fibrations mean over the basepoint.

Close #438.
errata for e26096b, unmarked
Merge pull request #435 from akissinger/master

Simplify type of D in proof that path induction implies based path induction
Merge pull request #434 from mikeshulman/arxiv

Makefile scripts for arXiv tarball
Merge pull request #439 from mikeshulman/whisker

Clarifying remarks about whiskering and Eckmann-Hilton
Merge pull request #440 from mikeshulman/hopf

The "fibers" of the Hopf fibrations mean over the basepoint.