Access token branch saif

FIles To Review

1..AccessTokenDataBase.cs
2..CustomException.cs
3.IAccessToken.cs
4.TokenAccessService.svc
5.AccessTokenFixture.cs

Feedback for this test - 
1. Asserting for length of 36 seems to indicate some special significance of that number which is not clarified in the following tests. Why not 40 or 50.. ? Also would just testing for a non-empty string not suffice?
2. The name is not really intuitive. It raises more questions than it answers like what is database is full, how do I know it is not full etc. A better name would be FirstGetTokenCallShouldSucceedTest().