try to convert tracker urls to unicode
Merge pull request #883 from LipuFei/fixes

Fixes
fix RSSParser
fix metadata injector
make FastI2I error messages more accurate
change metadata injector log level
add mid for candidates in debug frame

Conflicts:
	Tribler/Main/vwxGUI/DispersyDebugFrame.py
add debug prints for metadata bot
add debug command (print communities) for metadata bot
fix metadata injector