Fix small README typo: writes to .md.html, not .md
Merge pull request #24 from jasonm/patch-1

Fix small README typo: writes to .html, not .md
Drop 1.8 support and update deps (except listen)

Listen requires a bit more work... updating it in the next commit.
Upgrade listen
Merge pull request #26 from dmarcotte/drop-1.8

Drop Ruby 1.8 support and upgrade dependencies
Render task lists in readmes

Task lists are now render for readmes too, not just comments.  See
https://github.com/blog/1825-task-lists-in-all-markdown-documents