Merge branch 'ad/bisect-terms'

The use of 'good/bad' in "git bisect" made it confusing to use when
hunting for a state change that is not a regression (e.g. bugfix).
The command learned 'old/new' and then allows the end user to
say e.g. "bisect start --term-old=fast --term=new=slow" to find a
performance regression.

Michael's idea to make 'good/bad' more intelligent does have
certain attractiveness ($gname/272867), and makes some of the work
on this topic a moot point.

* ad/bisect-terms:
  bisect: allow setting any user-specified in 'git bisect start'
  bisect: add 'git bisect terms' to view the current terms
  bisect: add the terms old/new
  bisect: sanity check on terms

diff --cc bisect.c
Simple merge