Add support for tabular component layout

- refactor markdown renderer to move most functionality out into block code renderer

Signed-off-by: Nicole Sullivan <nsullivan@pivotal.io>
Add docs for tabular component rendering

Signed-off-by: Nicole Sullivan <nsullivan@pivotal.io>
Fix CI errors.

- Remove method with invalid Ruby 1.* argument syntax
- Require haml as a development dependency so it can be used in tests

Signed-off-by: Nicole Sullivan <nsullivan@pivotal.io>
Safe-require haml in block code renderer.

Signed-off-by: Geoff Pleiss <gpleiss@pivotal.io>
Move BlockCodeRenderer require statement into MarkdownRenderer
Merge pull request #154 from gpleiss/feature/tabular_code_examples

Tabular code examples