Added support for kramdown, redcarpet and custom formatters.
Removed gemfile.lock from project
Merge pull request #142 from Antek-drzewiecki/swagger_markup

Added support for kramdown, redcarpet and custom formatters.
Fixed NoMethodError StandardError bug #142, added specs, changed throw of StandardError to ArgumentError.
Merge pull request #143 from Antek-drzewiecki/markdown_throw_fix

Fixed NoMethodError StandardError bug #142
Added support for Rack::Multipart::UploadedFile parameters, fixes #47.
Updated CONTRIBUTING.
Added RELEASING.md.