Fixing back compatibility issue which affection extensions.
For original version see: https://github.com/WindowsAzure/azure-sdk-for-media-services/blob/v3.0/src/net/Client/StorageAccountBaseCollection.cs
3.0 was not backward compatible with 2.4.* and it was communicated.
3.0.0.3 should be backward compatible from 3.0.*
Merge pull request #80 from gtrifonov/dev

Fixing back compatibility issue which affect extensions.