Initial hack on the artwork fetching
Fix the release lookup link
Intelligently cache online artwork searches
Make the fetching fire-proof
Fixed a typo
Move the semaphore to its own class and add some tests for it
Fix the artwork fetcher exceptions

HttpClient returns a HttpRequestException, not a WebException (Thanks MS for not documenting exceptions on async methods)

Additionaly, the release id lookup can fail with a "Not Found" status, which is completely valid in this case, so don't throw an exception and just return null.
Just return the cache key when fetcghing an artwork online
Release the semapohre if we return early
Release the semaphore under all circumstances and queue all cache operations
Properly escape the search query
Only release the semaphore if an exception is thrown
Introduce the actual method to kick off the artwork lookup
Fixed the name
Try every release that has a score above 95
Fix the Lucene query escaping
Added a bunch of unit tests
Omg Lucene
Merge pull request #73 from flagbug/artwork-download

Automatic album artwork download