Added getting lyrics from text files

This needs work on the XML converter
New way of building XML

Less error-prone
Allows setting both attirbutes and text-data on a single element
Some work on encodings
Getting lyrics from chartlyrics.com
Merge branch 'master' into lyrics

Conflicts:
	api/media.py
Scanner: added a callback interface to report progress
CLI: display scanning progress every 5 seconds