Re-written disclaimer

- The original disclaimer violates the end tag nesting rules
- There were two different disclaimers for both languages
Applied further changes to ZipWriter

Instead of throwing an exception, you better set the date to zero, so a
date prior 1980-01-01 00:00 UTC will also be possible.
Added support for directory date
Applied small optimization

To prevent redundancy
Fixed formatting
Added favicon within ACP
Merge branch 'master' of github.com:WoltLab/WCF
Fixes versionable database objects
fix travis error
Fix MySQLDatabaseEditor
Fix uninstallation of plugins with versionable database object
Fixed resize of cached images
Updating minified JavaScript files
Fixed import issue
Fixed import of embedded attachments
Merge branch 'master' of github.com:WoltLab/WCF
Merge branch 'master' of github.com:WoltLab/WCF
Fixed spoiler bbcode
Merge branch 'master' of github.com:WoltLab/WCF
Added unique import hash