oga gem is automatically required by the aws gem
the oga gem retains about 1mb of memory, aws now uses nokogiri
This also removes the html normalize from the pretty text specs that was
a fair bit buggy as the polls test shows.
This adds the markdown.it engine to Discourse.
https://github.com/markdown-it/markdown-it
As the migration is going to take a while the new engine is default
disabled. To enable it you must change the hidden site setting:
enable_experimental_markdown_it.
This commit is a squash of many other commits, it also includes some
improvements to autospec (ability to run plugins), and a dev dependency
on the og gem for html normalization.
