Introduces a preview window that appears when the screen is wide enough,
removes old preview button, adds a draft-public switch, adds variety of
preview options which are not hooked up yet.
Goes along with cms commit fa3738a9f4c5181eabf18a77ca89792d31592250
1. Refactored some gridfield styles to enable reuse (created a mixin
file to hold mixins that generate specific css objects/elements).
2. Made some scss comments use // so they wouldn't appear in generated
css
1. Add arrows to edit dropdowns
2. Adjust lightened fields so they don't look like input boxes, and fix
rgba colours
3. Add ability to click file names to edit
4. Add feedback when edit button is hovered
5. Add feedback if a file has been opened for editing and shut again
(saved changes, unsaved changes, unchanged)
6. Add ability to open and close all files to edit them all at once
7. Add overall feedback for file uploads, and fix NaN error
8. Fix up area to match design
9. Fix error messages so they fit in the provided space
10. Fix case where a single uploaded file errors
Added classes to dropzone when dragging and dropping files. Added
styles to the dropzone when a file could be dropped. Added a clearfloat
mixin to the mixins file.
