Fix last visit time of conversations (phpBB3, SMF2)

Fixes #10
Adapt to WoltLab/com.woltlab.wcf.conversation@ac8c26c4d08626268f742b61174e513cab7c9158

Closes #9
Remove obsolete code in SMF2xExporter

see 10cf22fea65c3726a2c2a2d8ee64a4ec696dd178
Changed class name references
Removed obsolete code
Export smilies (vB3)
Preparing release 2.0.0 Beta 7
Updating release date
Merge branch 'master' into vb3
Add FORUMPERMISSION bits (vB3)
Export ACL (vB3)