Merge pull request #1 from Alxandr/master

Merged changes back into my fork.
Added an extra debugger line.
Added an Error extension method to get the nice string from libspotify, added better login error handling to the TestClients
Moved the extension method into the proper file. Fix for Issue #27. Fixed TestClients.
Added guard in logn callback, normalized line endings in Stdafx.h
Removed stray logger line.
Added Assembly ExtensionAttribute
Working to resolve some warnings.

I get tons of "LNK4248: unresolved typeref token (xxxx) for 'sp_xxxxx';
image may not run"
Merge pull request #28 from EraYaN/master

Fix for Issue #27 and an extension method for the Error enum.