Remove "Provider" post-fix.

[dmitry-a-morozov]

SqlCommandProvider -> SqlCommand SqlEnumProvider -> SqlEnum

"Provider" post-fix is noise and was used initially mostly because lack of TP dev experience. This will be BREAKING CHANGE. The first rename can create naming conflict problem when both .NET BCL System.Data.SqlClient and FSharp.Data namespaces are open. Workarounds:

• Use full type name e.g. let cmd = new System.Data.SqlClient.SqlCommand()
• Use type alias for BCL types from System.Data.SqlClient Overall feels like not a big deal because it's very rare that both raw ADO.NET and FSharp.Data.SqlClient used intensively in a same file.

P.S. SqlProgrammabilityProvider becomes SqlClient. See issue #161