Add ImageEncodeTask to encode a disk image to a different profile
and directory.
* morituri/common/encode.py:
Add lossy encoding profiles for mp3 and vorbis.
Rename muxer to tagger since that's what we use it for.
Do progress probe after level to make sure we get samples for
offsets.
* morituri/rip/image.py:
Add rip image encode command.
* morituri/common/program.py:
Extract a common method to get textual representation of
AccurateRip results, and test it.
* morituri/rip/cd.py:
* morituri/rip/image.py:
Use the method.
