Support F# OTB

Hello guys, thanks for the awesome job on Dapper best sql tool ever :)

I would like to talk about F# and Dapper.
Right now I have a lot of duplicate code in my projects specially because of DU and Option types.

For instance I have to write code like this for every single DU

type SkuClassificationTypeHandler() =
    inherit SqlMapper.TypeHandler<SkuClassification>()
    override this.Parse (value) =
        match value :?> string with
        | "A" -> A
        | "B" -> B
        | "C" -> C
        | "D" -> D
        | "E" -> E
        | _ -> E
    override this.SetValue (p, value) =
        p.DbType <- DbType.String
        p.Size <- 1
        p.Value <-
            match value with
            | A -> "A"
            | B -> "B"
            | C -> "C"
            | D -> "D"
            | E -> "E"

And this for Option type

type OptionHandler<'T>() =
    inherit SqlMapper.TypeHandler<option<'T>>()
    override __.SetValue(param, value) =
        let valueOrNull =
            match value with
            | Some x -> box x
            | None -> null

        param.Value <- valueOrNull
    override __.Parse value =
        if isNull value || value = (DBNull.Value :> obj)
        then None
        else Some (value :?> 'T)

SqlMapper.AddTypeHandler (OptionHandler<int>())
SqlMapper.AddTypeHandler (OptionHandler<string>())
SqlMapper.AddTypeHandler (OptionHandler<MyRecord>())

Is it possible to support F# specificities OTB? Maybe for 2.0?

The issue names SqlMapper.TypeHandler and SqlMapper.AddTypeHandler as the relevant entry points; start by tracing how those handlers are registered and invoked. Done would mean F# DU and Option cases are supported out of the box without the repeated per-type handlers shown, with coverage for the examples in the issue.