Update project's Google API key (...again)
Move blogger api notes to blogger.md
Introduce draft of a Blogger API back-end for comment posting
Introduce blog comment preview (before submission)
Blog comment form plumbing

* Recaptcha is not functional.
Refactor blog_posts & blog_comments to use programmable callbacks
Use captchapng module && move blog API funcs to lib/blogger.js
Fix CAPTHCA verification
Introduce form validation for blog comments