Clarified git branch -a use.
Clarified git branch -a use.

Previous version implied that git branch -a clearly showed
that our master branch was ahead by one commit.  This was
misleading.  git branch -av states very clearly if a certain
branch is ahead by any commits.

crystalzhaizhai/cs207_yi_zhai,IACS-CS-207/cs207-F17,crystalzhaizhai/cs207_yi_zhai,IACS-CS-207/cs207-F17