make lib.logo generic
abstract xy validation
create avatar route
profile sidebar
add border to button_round

only a slight difference but differentiates button
from background
fix follow button spacing
event stream
update avatar placeholder image

I created the new image myself from photos of team members.
So it should be free to use
check if really deleted
settings

copied from instance
nicer logo settings design
set avatar width explicitly for event stream

lib.logo does not seem to take the x value into account when resizing
check permissions for "upload avatar" button

compability with #644 readonly installation
nicer logo settings design also for thumbnail badges

"Thumbnail" heading should have some top-margin.
However that issue was not introduced in this commit so
I won't spoil this commit with a fix
add installation setting use_avatars
add a small note that the uploaded images should be square

as users don't want eggheads.
restrict possible image scales

This is done to prevent attackers from using up a lot of disk
space by requesting many differently sized or very large scales
of an image
use fallback avatar for deleted users

the avatar url can be generated but will 404 as the user
Add missing image scale size 64px
Merge pull request #641 from xi/feature-430-avatar

User avatars