Make 'Changeset detected' look more different from 'No Changeset found'

[eoghanmurray]

Problem

The automatic github message is very helpful, but many times I've missed that the message says 'No changeset found' after a quick scan.
The problem I think is that the yellow warning symbol is the only scannable difference, and the user icon for the changeset-bot is the same as the 'Changeset detected' icon — so sometimes visually scanning, I'll see the pretty butterfly which belongs to the github bot and think there's a changeset already added (The tick as suggested in #27 would help with this).

Proposed solution

• Make the success message significantly more brief than the 'No changeset found' message
  Both the 'detected' and 'not detected' versions of the message are pretty much the same length and have the same elements. In the success message, the 'Not sure what this means?' message could be easily omitted, or added as an inline link instead. The long 'Click here if you're a maintainer ...' message could also be much shortened to 'Add another changeset' as this is very much now a less critical call to action