Fix references to mejs.players[0]
Remove extra fieldset from channels list
Fix the label for the poster image
Make the first element the h1

This should be the first element to provide context for the entire page.  Moving the 'save' button up also makes sense to me.
Instructions should come first.
The URL should no longer be editable
Move hidden fields to the same place

Makes it easier to read the form markup when editing it.  The form also used to be used for both editing and creating media, but not it is only used for editing, thus the check for if media exists is not needed.
Place list items in lists
Improve code readability
Remove uneeded `onclick` events
Merge pull request #180 from mfairchild365/media-edit

Improve the media edit page (standards, useability)