tidy up avatars styles
fix #398
error handling nit
History now remembers last used Expand All/Collapse All.
Now line numbers are not selectable.
The border actually is visible, removed comment.
Simplified part of less code
Styled row numbers of diffs viewer.
Added spacing on "position" rows of diff viewer.
Merge remote-tracking branch 'FezVrasta/rows'
Changelog...
fix #475
issue #278
Version 0.13.12
Update README and screens
Merge pull request #487 from SAPlayer/readme-screens

Update README and screens
issue #484
issue #437
Added icon to the history viewer which opens the mentioned file for editing.
+css