Handle capitalised 'Summary:'.
Delete summary from YAML front matter.

Jekyll chokes on Markup link references, and it's way too
much hassle to strip them out.
Fix 'content' colons in YAML front matter.
Improve 'colons' test.
Add 'colons' to 'convert everything'.
Add layout to front of YAML.
Rename 'convert quotes' method.
Convert ellipsis, en-dash, and em-dash ascii codes.
Merge branch 'release/1.1.0'