Synced editor scrolling PoC.
Moves Markdown Editor from vendor to discourse.
Make polls work better on multi-language forums.
Merge pull request #2214 from vikhyat/poll-plugin

Make polls work better on multi-language forums
Merge pull request #2100 from velesin/synchronized_editor

Synced editor scrolling PoC.
Merge pull request #2125 from vikhyat/css-variables

Allow importing Discourse styles in custom stylesheets to modify vars
Rename normalize.css -> normalize.scss to allow @importing from SCSS.