Add more languages to the fenced code snippet

- Elixir
- HTML
- Shell
Use the ruby18 shim to generate the title
Use the ruby18 shim in the line computation
Add rb as a shorthand for Ruby
Match single quotes in code blocks
Merge pull request #13 from stevekinney/add-rb-as-ruby-shorthand

Add rb as a shorthand for Ruby
Merge pull request #14 from stevekinney/match-single-quotes-in-code-blocks

Match single quotes in code blocks
Detect and respect YAML frontmatter
Custom font for YAML frontmatter
Merge pull request #16 from stevekinney/support-yaml-front-matter

Detect and respect YAML frontmatter
Merge remote-tracking branch 'upstream/master'

Conflicts:
	Syntaxes/Markdown Redcarpet.tmLanguage