Update project to use devtools
Rename specs to match mutant naming convention
Remove unnecessary local variable assignment
Update .rspec to use RSpec 2 settings
Remove an unnecessary assignment
Fix reek.yml to use less brittle format

* In 1.8 the last element cannot have a trailing comma. Switching to
  the format using a hyphen allows each entry to be identical, so
  that if they are sorted it won't break the config.
Upgrade gem dependencies
Add coveralls to spec helper
Update travis configuration
Update copyright date
Change markdown syntax in README
Update badges to match axiom-types