clean up
big API change - execute params instead of props

- Parameters to AsyncExecute/Execute replace properties
- TVP & RETURN_VALUE are not done yet
TVP for execute with params fixed
AsSqlCommand better clone

Return value and out params are not done yet
minor SP-direct related bug
typo
docs, bug fixes

* Input parameters provided as arguments to AsyncExecute/Execute instead
of properties on command instance.
* Handle user-defined data types mapped native SQL Server types like:
CREATE TYPE dbo.Name FROM [nvarchar](50) NULL
* Added System.Xml into sys libs dependecies
minor spelling fix in docs