Added a step to create templates on the fly
Support template chaining for partials
Merge branch 'v3-stable' into feature/chained_templates_partials

Conflicts:
	middleman-core/lib/middleman-core/core_extensions/rendering.rb
Make rubocop happy
Merge pull request #1338 from dg-ratiodata/feature/chained_templates_partials

Chained template parsing failed if parent is "html.erb" and child is "html.md.erb"