Changes to category_links filter in category_gen.rb
Display tweaks for post formats

flickr.rb
 - Changed title and alt attributes to double quotes to prevent errors with apostrophes in image titles

summary.html
 - Moved video into header & added post.content to look more like the image post format
 - Changed flickr image size for image posts to d (not sure why this should be the case, but m is not medium for actual images)
 - Added standard meta block back into image post format (it looks better I think)

video.html
 - Added oembed tag for video before the content tag

Took liquid tags & markdown out of the beginning of the following posts:
 - George's First Year
 - My Language Challenge
 - Mandarin Progress Month 1
 - Mandarin Progress Month 2
 - Mandarin Progress Month 3
 - Mandarin Progress Month 4
 - View over Loch Fyne

Set maximum width of post summary thumbnails to 150px;
General site adjustments to get it ready for production

 - Added author pages
 - Added all remaining category pages
 - Removed category generator classes from category_gen.rb
 - Added emoji_for_jekyll gem to Gemfile
 - Added relative_permalinks: false to _config.yml and updated permalinks in page yaml front matter