Update to current version of darthapo/liquid
Change order of operations for preview liquid and markdown

Change from [content > markdown parse > liquid parse] to [content > liquid parse > markdown parse] because markdown likes to clobber quotes and adds autolinks to urls.
Implement the include tag from Jekyll
Changelog and version bump
Merge pull request #651 from rebelzach/fix-include

Implement Jekyll style includes
Merge branch 'refs/heads/master' into gh-pages
rebuild