Parse less and scss files

This pull request is for [Simple support for LESS/SCSS](https://trello.com/c/KoK6kPtp/1190-m-simple-support-for-less-scss-in-key-brackets-features).


We do need this, because the active editor might become null, and in that case it's correct for this.editor to become null (and we should skip the contents of the if).