small fixes for SettingsDialog
remove broken test_vod
small fix for metadata-injector.py
cleanup imports and fix import *
fix MainFrame import
Fix channel.py import
cleanup tribler_main.py
remove API.py
fix logger.exception().
fix test_merkle_msg import
Merge pull request #473 from LipuFei/small-fixes

Small fixes + cleanup
Changes to pymdht
Cannot just call logger.exception needs a message
Improved prefetching
Refactored has_torrent
Fixed torrentcollecting test
Some more logging
More debug
More debug
Reducing torrent sleep interval during tracker_check