* Massive gf rewrite for better extensibility.
* Greatly improved asset support.
* Provide command line <C-R><C-F> with same logic as gf.
* Support Rails 5 rails/rake unification.
* Selectively delegate :Rails to rake on older Rails versions.
* :Rails supersedes :Rake as default task dispatcher.
* Add channel and serializer support.
* Support tab/vert style mods on Vim 8.
* Provide :Clog to load logs into quickfix list.
* Update syntax highlighting for Rails 5.1.
* Use filetype=eruby.yaml for yaml files.
* Refactor to use projections for much of internal implementation.
* Enable :Econtroller to edit controller concerns.
* Rearrange and clean up help.
* Drop legacy (non asset pipeline) Less CSS and CoffeeScript support.
* Formally deprecate R commands.