support custom primitive types

[chaowlert]

Hi,

Thank you for your library. I'm using your library and ran into issue where some classes cannot map. But it should be just copied reference to target.

In my scenario, the class is DbGeography which is standard EF type. Even it is class, but it represents primitive type similar to string.
And every time mapper maps this class, it will throw exception, because this class has no constructor.

The example usage is TypeAdapterConfig.GlobalSettings.PrimitiveType.Add(typeof (DbGeography));

[eswann]

Nice, thanks for the pulls, will review and pull.

[eswann]

After merging in the pulls, I was seeing many tests failing....I reapplied the change sets and appears that test are now functional. Would like to see a unit test for this. Thanks!