Misc fixes

Fixes #3, #9, #10, #18. 

Removed `is-hidden` from buttons, since they simply don't get rendered into the DOM if you're in a view for posting. Still need to figure out the best way to handle animations.

Using the File API to append the file name after selecting an image to upload.

The Node app'll now do a check for an existing image folder on boot, and will make one if there isn't one present. 

Using the triple-stash to keep Handlebars from escaping the text in a way that was messing up Markdown syntax.