Merge pull request #157 from annando/master

Bidirectional twitter sync - and some small fixes
SN connector: small fix for the settings page
Merge pull request #158 from tobiasd/little_SN_fix

SN connector: small fix for the settings page
Merge pull request #159 from annando/master

Facebook sync
!isset() check stopped working, empty() might be the better choice anyway
Merge branch 'hotfix/jappix-groupchat'
Merge pull request #160 from tugelbend/master

!isset() check stopped working, the empty check works (for now)
Merge remote-tracking branch 'upstream/master'
fbsync: Temporarily removed the missleading option to import the contacts