Fixed some errors in the Jekyll markdown blog posts, this should close #620 :
Wrap titles that have a colon (:) character in them in quotes - causes a Jekyll server error that is currently causing the empty dates listed at the top of https://operationcode.org/blog. Jekyll posts with a colon in the FrontMatter title properties must be wrapped in quotes: https://github.com/jekyll/jekyll/issues/549
Center all images by wrapping in reusable element w/ utility class
Fix typos in markdown posts and BLOG_POSTING_GUIDE.md
Add Medium attribution/link to end of externally-authored posts that were missing it
Fixed some errors in the Jekyll markdown blog posts, this should close #620 :