make Metric#total optional
Allows configuration of "lower number is better"

rebase of #67
Merge branch 'master' into lower-is-better-rebase

Conflicts:
	lib/tricle/metric.rb
	lib/tricle/presenters/metric.rb
change css classes to "good" and "bad"
Update "lower is better" readme section
re-remove metric
Merge branch 'master' into optional-total

Conflicts:
	spec/unit/email_helper_spec.rb
mail view hit 2.0
backwards compatibility for ActiveSupport 3

closes #30
Merge pull request #57 from afeld/optional-total

make Metric#total optional
Merge pull request #71 from afeld/bump-gems

Bump gems
create percent_change_class method
correct+tweak lower->better instructions
Merge pull request #70 from afeld/lower-is-better-rebase

Allows configuration of "lower number is better"
Merge remote-tracking branch 'origin/master' into sparkline

Conflicts:
	lib/tricle/presenters/metric.rb
	tricle.gemspec
Merge branch 'sparkline' into sparkline-inline

Conflicts:
	lib/tricle/aggregation.rb
	tricle.gemspec