fix nil path when not using gist cache
Added safe_wrap (escaping markdown and textile) to cached gists. Closes #917
Merge pull request #916 from Keithbsmiley/2.1

Fix nil path when not using gist cache
Switched Markdown processor from rdiscount to redcarpet
Fixes for Redcarpet
- Removed unnecessary content filtering for escaping markdown
- Escaping codeblocks defaults to false and can be enabled by passing escape:true
- Backtick codeblocks are automatically escaped when using Textile
- Scoped styling of .highlight divs to figure elements
Enabled nice default extensions for redcarpet
Merge branch '2.1' of git://github.com/imathis/octopress into testing-2.1

Conflicts:
	plugins/octopress_filters.rb