pull section rendering into method for speed boost
README updates

- additional notes about differences from AsciiDoc
- use + for monospaced text instead of `
- mention Rubinius and Ruby 2.0.0 in list of supported runtimes
- move additional urls into attributes, update names
- other minor edits
Merge pull request #194 from mojavelinux/readme-updates

README updates
Merge pull request #195 from mojavelinux/section-render-perf

Pull section rendering into method for speed boost
Remove redundant snippet
allow header attributes to resolve author & rev info
Restore first line
Merge pull request #197 from mojavelinux/header-attributes-fix

Allow header attributes to resolve author & rev info