Migrate from Shared Caching to Windows Azure Cache Service

The current project uses the Nuget package for Windows Azure Shared Caching. However, the [MSDN documentation](http://msdn.microsoft.com/en-us/library/windowsazure/gg278356.aspx#SharedCaching) says that service will soon be retired in favour of new Windows Azure Cache package. This pull request simply makes that migration.

I simply followed the instructions on the following page:

http://msdn.microsoft.com/en-us/library/windowsazure/dn386110.aspx