It seems worth mentioning explicitly if Dapper works with PostgreSQL or not. I assume it does based on the remark that "it works across all .net ado providers", but am not sure because it's not mentioned explicitly...
Allows use of IDictionary<string, object> as parameter objects.
I'm assuming that the && was a mistake, and that this logic should
handle both of the types equally well.
Also allows .NET 3.5 to use the IDictionary case.