Access token with timestamp

1. Necessary Modification done as per Comments.
2. Timeout Based Token Released Method Implemented.
Files To Review:
1. AccessToken.cs
2. AccessTokenParameterInspector.cs
3. HashSetBasedAccessTokenDb.cs
4. IAccessToken.cs
5. IAccessTokenDataBase.cs
6. TokenAccessService.svc
7. AccessTokenFixture.cs