Shorter code for populating expanded_contains
Merge branch 'master' of github.com:isagalaev/highlight.js
Zeroing relevance of comments starting with `;` as they take over a lot of C-like languages.
Using standard keyword lexing for Ruby.

Ruby keywords don't contain any fancy symbols anyway, and
standard lexing protects keywords surrounded by dots.
Import news from the site into CHANGES.
Unify relevance counting into a single variable.

Historically, we accumulated relevance coming from parsing modes
and relevance coming from keywords in two separate variables. The
need for this never materialized. Time to simplify this.
Documented the rest of backwards incompatible changes in CHANGES.md.