Fix calculation of branch coverage when a class has no branches.
Update CHANGELOG.md
Refactor line and branch rate fixes.
Merge branch 'master' of https://github.com/venmo/slather
Update CHANGELOG.md to mention changes under version 1.5.4.
Merge pull request #40 from tarbrain/master

Fix calculation of branch coverage when a class has no branches.
Merge remote-tracking branch 'upstream/master'