Adds missing reserved tag in OptionPIP

Closes #1265
Adds missing style cache reset after style import
Fixes issue when installing style with preview image during setup

Fixes #1173
Improved initial jump to an anchor
Merge branch 'master' of github.com:WoltLab/WCF
Updating minified JavaScript files
Removed fixed user panel
Removed fixed user panel
Merge branch 'master' of github.com:WoltLab/WCF
Updating minified JavaScript files
Fixed support for absolute URLs
Merge branch 'master' of github.com:WoltLab/WCF
Improved editable item list
Updating minified JavaScript files
Fixed previous commit
Merge branch 'master' of github.com:WoltLab/WCF
Updating minified JavaScript files
Adds supported for framed canvases