More adsi type support, less meterpreter crashes

![ADSI types](http://i.imgur.com/mruWy6W.jpg)

Meterpreter crashed in cases where results were of ADSI types that were not supported. This changeset fixes that and adds more support for other types as well.

Thanks to @Meatballs1 for finding the bug. Hopefully this will move us a little closer to something that doesn't break horribly.