only display edit link for attachments if allowed - fix #8365
do not protect Controller#perform_caching

set the config option instead.
use strong params in avatar controllers - fix #8341
don't alter the type of @group - fixes #8338
groups now have a single invite resource
remove rails 3.0 notes [skip-ci]
bring back styling for votes
more vote css tweaks
make sure wiki styles are not applied to sidebar & menu

the wiki pages have a .wiki set on the main content area. This also applied the wiki styling. Now we only apply it if the .wiki is inside the article section.
Revert "do not protect Controller#perform_caching"

This reverts commit ac3b9195d9c009b89894a4c3fbcefd0490c8bb25.
fix avatar uploads - fixes #8341

when setting perform_caching to true we also protected the method
-> broke external call of that method. using hide_action instead.

Also moved this into a shared module and changed avatar into singular
resource for groups and me
Merge pull request #101 from azul/bugfix/page-permissions

Bugfix/page permissions