Bidirectional Statusnet sync, bugfix for posting facebook comments and some title improvements

**Important!**
This pill request must not be accepted before this pull request was accepted: https://github.com/friendica/friendica/pull/932 (It needs functions and constants from the core)

This pull request has the following content:
* It is now possible to import a statusnet timeline from an existing statusnet account. The code is taken from the twitter addon.
* fbpost: When posting comments to facebook, links vanished - this will not happen anymore
- fbpost/fbsync: You can now address posts to selected facebook contacts. To make this work, further information in the contacts is needed. This information is taken when these contacts are posting content or when they are added for the first time.
* The connectors titles are now having more details. Instead of e.g. "Wordpress" it is now called "Wordpress Export". This isn't done with all connectors by now - but with many of them.