Post manager improvements

Noticed during testing:

• Button CSS needs pixel-perfection:
  • delete icon is misaligned:
  • unpublish is having a bad day (icon alignment and outline):
• The icons are not consistent with one another (different line styles, corner radius and widths)
• The 'create new post' form is at the bottom of the page, after a list of however many posts there are. I think the form should be above the fold.
• The list of posts doesn't truncate. I think it should allow pagination or infinite scrolling.
• Ideally it should be possible to filter and sort the posts list.
• When there are many posts, the action buttons are quite a heavy aspect of the design. Could we hide or lighten them, but restore visibility/colour when the row is moused over?
• The actions column takes up too much space IMHO. I think the columns should be spaced like:
  1. number: fixed width
  2. title: expand to fill space
  3. author: maximum and minimum width so that author names can adjust presentation based on space 4: status: fixed width 5: actions: fixed width
• Double-clicking a title adds an input field with the title alongside the already rendered title. It should be contenteditable so the title can be edited in-place.

Some of the above could be broken out into separate issues.