Allow to pass badges to background process
Add notifications on proposal badge assignment/removal
pep8
cleanup unused code
add sectionpage tutorials
enable diff view on variants by default
new comment design

-   all (sub)comments are visible by default
-   the show_comments button is obsolete
-   the new_comment button gets the same arrow as
    showhide_buttons
-   lines on the left make it simpler to understand the
    tree structure
-   the metadata is reordered
-   new comment forms don't have their own heading
refactor comment design with robin
slightly lighten fg1 color
white background in all overlays
Merge pull request #573 from xi/feature-sectionpage-tutorials

sectionpage tutorials
minor css changes

some tweaks I needed for implementing the new grüne nrw theme.

most importantly I gave the badge background image a white
background and added an html element wrapping the subnav and
search.
pep8
striped down new/edit section forms
fix section delete ret_url
count deleted sections for new section postfix

The idea to append the number of existing sections to each new
sectiontitle had a serious flaw considering one can delete
sections.

I fixed this be counting children instead of subpages.
As far as I understand the subpages are all children which
have not been deleted.
Merge pull request #568 from nidico/feature-badge-notify

Add notifications on proposal badge assignment/removal
Merge pull request #576 from xi/feature-add-section-form

add section form
cleanup unused javascript
consider that comments may be deleted