Improve the bindings about fable-react HOT 2 CLOSED

// Contains the generic React helpers
namespace Fable.Helpers.React

[<AutoOpen>]
module Common =

    [<Import("createElement", from="react")>]
    let createElement(comp: obj, props: obj, [<ParamList>] children: obj) =
        HTMLNode.Empty :> ReactElement

    let inline ofFunction<'P> (f: 'P -> ReactElement) (props: 'P) (children: ReactElement seq): ReactElement =

    // Example
    /// Alias of `ofString`
    let inline str (s: string): ReactElement = unbox s

    /// Cast a string to a React element (erased in runtime)
    let inline ofString (s: string): ReactElement = unbox s

    /// Cast an option value to a React element (erased in runtime)
    let inline ofOption (o: ReactElement option): ReactElement =
        match o with Some o -> o | None -> null // Option.toObj(o)

    /// OBSOLETE: Use `ofOption`
    [<System.Obsolete("Use ofOption")>]
    let inline opt (o: ReactElement option): ReactElement = ofOption o

    /// Cast an int to a React element (erased in runtime)
    let inline ofInt (i: int): ReactElement = unbox i

    /// Cast a float to a React element (erased in runtime)
    let inline ofFloat (f: float): ReactElement = unbox f

    /// Returns a list **from .render() method**
    let inline ofList (els: ReactElement list): ReactElement = unbox(List.toArray els)

    /// Returns an array **from .render() method**
    let inline ofArray (els: ReactElement array): ReactElement = unbox els

module  Fable.Helpers.React.Html

type CSSProp =
    | AlignContent of obj
    | AlignItems of obj
    | AlignSelf of obj
    | Custom of string * obj

type Props =
    // Concatenation of HtmlProps & HtmlAttr
    | Key of string
    | Ref of (React.Element -> unit)
    | Custom of string * obj
    | Style of CSSProp list

// All the Html element helpers
let inline a b c = domEl "a" b c
let inline abbr b c = domEl "abbr" b c
let inline address b c = domEl "address" b c
let inline article b c = domEl "article" b c
let inline aside b c = domEl "aside" b c
let inline audio b c = domEl "audio" b c

module Fable.Helpers.React.Svg

type Props =
    // Concatenation of HtmlProps & HtmlAttr
    | Key of string
    | Ref of (React.Element -> unit)
    | Custom of string * obj
    | Style of CSSProp list

// All the Svg element helpers
let inline svg b c = svgEl "svg" b c
let inline circle b c = svgEl "circle" b c
let inline clipPath b c = svgEl "clipPath" b c
let inline defs b c = svgEl "defs" b c
let inline ellipse b c = svgEl "ellipse" b c

// Old api
rect [ SVGAttr.X model.AxisYWidth
       SVGAttr.Y (offsetY - model.RowHeight)
       SVGAttr.Width barAreaWidth
       SVGAttr.Height model.RowHeight
       SVGAttr.Fill "#fff" ]
    [ ]

// New Api
Svg.rect [ Svg.X model.AxisYWidth
           Svg.Y (offsetY - model.RowHeight)
           Svg.Width barAreaWidth
           Svg.Height model.RowHeight
           Svg.Fill "#fff" ]
    [ ]

    type [<RequireQualifiedAccess>] Treemap =
        interface Fable.Helpers.React.Props.IProp

type CustomType =
    | [<Flatten>] HtmlProps of Html.Props list