ImportFeeds: fix/disable/catch symlink usage on windows

[Schweinepriester]

... because it doesnt work?

but it seems possible: http://en.wikipedia.org/wiki/NTFS_symbolic_link
http://lifehacker.com/5496652/how-to-use-symlinks-in-windows

Traceback (most recent call last):
  File "C:\Python27\Scripts\beet-script.py", line 9, in <module>
    load_entry_point('beets==1.3.6', 'console_scripts', 'beet')()
  File "C:\Python27\lib\site-packages\beets\ui\__init__.py", line 967, in main
    _raw_main(args)
  File "C:\Python27\lib\site-packages\beets\ui\__init__.py", line 958, in _raw_m
ain
    subcommand.func(lib, suboptions, subargs)
  File "C:\Python27\lib\site-packages\beets\ui\commands.py", line 816, in import
_func
    import_files(lib, paths, query)
  File "C:\Python27\lib\site-packages\beets\ui\commands.py", line 788, in import
_files
    session.run()
  File "C:\Python27\lib\site-packages\beets\importer.py", line 262, in run
    pl.run_parallel(QUEUE_SIZE)
  File "C:\Python27\lib\site-packages\beets\util\pipeline.py", line 345, in run
    self.coro.send(msg)
  File "C:\Python27\lib\site-packages\beets\util\pipeline.py", line 158, in coro

    task = func(*(args + (task,)))
  File "C:\Python27\lib\site-packages\beets\importer.py", line 1076, in manipula
te_files
    task.finalize(session)
  File "C:\Python27\lib\site-packages\beets\importer.py", line 395, in finalize
    self._emit_imported(session.lib)
  File "C:\Python27\lib\site-packages\beets\importer.py", line 427, in _emit_imp
orted
    plugins.send('album_imported', lib=lib, album=self.album)
  File "C:\Python27\lib\site-packages\beets\plugins.py", line 379, in send
    handler(**args)
  File "C:\Python27\lib\site-packages\beetsplug\importfeeds.py", line 138, in al
bum_imported
    _record_items(lib, album.album, album.items())
  File "C:\Python27\lib\site-packages\beetsplug\importfeeds.py", line 127, in _r
ecord_items
    os.symlink(syspath(path), syspath(dest))
AttributeError: 'module' object has no attribute 'symlink'

[sampsyo]

Indeed; we should catch and skip this. There's related work in #710, where we're also adding a symlink wrapper that should emit sensible errors on Windows.