DHT ready check
Unit tests now use LibtorrentManager.is_dht_ready()
Add DHT check to get_metainfo + require minimum of 25 peers + delete DHT
check from unit tests
Merge remote-tracking branch 'upstream/devel' into dht_check

Conflicts:
	Tribler/Test/test_my_channel.py
Merge pull request #221 from egbertbouman/dht_check

DHT check