use jquery gem from rails-assets
handle DOS-formatted files
we're not using iframes for previewing anymore

An initial version used iframes for previewing.

This left-over CSS was interfering with videos in the preview.
remove admin.js from the build step (as it's only used in dev)
remove pry-debugger
added create-post.rb: it creates a post, opens it in $EDITOR & browser
support tags
default to displaying help when no title is provided