Many commands and plugins use `item.write()` to update tags. Since the success
of the call is not critical to the functionality of most consumers we want to
catch any exceptions, log an error and continue with our task. The new method
encapsulates this logic.
This fixes#675.
The delete() method on Mutagen objects writes the file directly. Calling
save() was unnecessary and, in at least one case we found, could inadvertently
preserve non-standard tags that Mutagen did not understand.
* Adds support for importing/managing .wma and .asf files
* Adds support for all available ASF tag equivalents
* Adds two utility methods for (un)packing embedded ASF pictures
* Modifies scrub plugin to work around the lack of a delete method on
ASFTags object.
This is the first of several commits that will modernize the beets codebase for
Python 2.6 conventions. (Compatibility with Python 2.5 is hereby abandoned.)
