Release 1.8.1
Merge branch 'master' into metrics

Conflicts:
	Gemfile.lock
	gemfiles/rack.gemfile.lock
	gemfiles/rails2.3.gemfile.lock
	gemfiles/rails3.0.gemfile.lock
	gemfiles/rails3.1.gemfile.lock
	gemfiles/rails3.2.gemfile.lock
	gemfiles/rails4.gemfile.lock
	gemfiles/rake.gemfile.lock
	gemfiles/sinatra.gemfile.lock
	honeybadger.gemspec
	lib/honeybadger.rb