Remove unused enqueue script method now that CSS is inline
Add proper text/css type to inline style element
Use admin_head to output CSS further into HEAD element

Using the add_admin_menus hook was causing our style to be output
right at the beginning of HEAD, which caused strange issues with
other parts of certain pages. admin_head is the right place for this.
Merge pull request #178 from washingtonstateuniversity/bug/admin-css

[PR] Fix: Early style output caused issues with 4.0 media library