Remove deprecated `shared_templates_api`

If we're doing a v2, we probably don't need this. It just adds cruft.
Merge branch 'master' into prep-for-v2-release
Remove helpers api.

Helpers are accessible via global context.
Support rails v2.3
Merge remote-tracking branch 'origin/pr/95'
Merge remote-tracking branch 'origin/pr/102'
Update CHANGELOG.
Don't butcher all template errors in Rails 4
Update CHANGELOG.
Update Haml-Coffee
Release 1.13.0
Update CHANGELOG. [ci skip]
Link missing issues in CHANGELOG. [ci skip]
Link missing users to CHANGELOG. [ci skip]
Revert "Remove helpers api."

This reverts commit d439a3bd3221e2e7862699b2499c1a78fa747850.
Update CHANGELOG.
Remove version skip hint.
Release 1.13.1
Make helpers API not dependant on Rails. (Fixes #109)
Release 1.13.2