Link the owner image to their github profile.

This temporarily provides more info about the owners of crates, without
having to find the repository or recognise the image (temporary until
crates.io has its own profile pages).
Tweak some alignment relating to profile images.

The personal logged-in avatar was a little too high. Fixes #60.

The vertical margins around a persons' personal information were too
large, causing the image to be misplaced.
Merge pull request #61 from huonw/user-link

Add user-links & tweak alignment