Switch to 2.1
Remove literal lang name from class, fix #2284

If code language is C classes for comment and language are the same
Update tests

Remove language literal from class in test/test_redcarpet.rb
Switch 2.1 to 2.1.1
Merge pull request #2290 from penibelst/travis-workaround
Update history to reflect merge of #2290 [ci skip]
Merge pull request #2292 from mtcomscxstart/code-class-fix
Update history to reflect merge of #2292 [ci skip]
Set content-type to text/html with utf-8 charset.

Fixes #2289
Update history to reflect merge of #2289 [ci skip]