BLOB Serializer support added

I hope these two separate commits are OK. I noticed the TimeSpan I submitted to Frank's repository had been merged here so I had to change the unit tests for BLOB to include it in the supported types. I wanted to leave the separate commits there to demonstrate unit test coverage (and because I had to switch machines from OSX to Windows to run the unit tests :)).

No serializers are included, just the delegate implementation in the unit test project. 

I was also wondering if DateTimeOffset should be added as supported data type? It goes nicely into 16 bytes (or less) and while it can be handled by the BLOB serializer this would be good addition.