Merge pull request #189 from annando/master

Mark facebook and facebook_restrict as unsupported, change version number of fbsync.
Merge pull request #190 from annando/master

pumpio: wrong date, fromgplus: better support of albums
Merge pull request #191 from annando/master

pump.io: preventing that a reenabling of the mirror option causes a flood of old posts
Merge pull request #192 from annando/master

buffer: Export to app.net now is in Markdown (can be made better)
Merge pull request #193 from annando/master

Buffer: Improvement for posts to app.net.
Merge pull request #194 from annando/master

Export connectors now are using the "plaintext" function, improvements to tumblr, short post detection for wordpress
Merge remote-tracking branch 'upstream/master'
Facebook: First changes to make the connector maybe work with the second version of the Facebook API
Twitter/Facebook: New functions for expiring of imported posts from twitter and facebook.