Image editor updates

[GraemeFulton]

Just done some fixes to the image editor, here's how it's looking:

imagedit.mp4

The main updates are:

• scale without losing focus
• close editor toolbar when uploaded image

Fixes:

• The menubar was losing position when the image is rerendered caused by size changes:

rerender.mov

To fix this, I position the toolbar based on the horizontal axis using left-start of the popover options, then use css margin to move it above image:

done.mov

To do:

There's still a few issues with the image component, so they're next:
#44
#41
#45