Instructions to ensure 'rake gather' grabs the latest mkdio.h.
discount sources up to v2.0.7
Option for Discount footnotes flag.
Update Rakefile to no longer use #{RUBY}, which is no longer defined by default.
Fix gemspec to include setup.c for the native extension.
Merge pull request #73 from davidfstr/master

Footnotes support. Bump Discount to 2.0.7. Compile on Ruby 1.9.3.