type StoreValue should include Store[] and StoreBaseValue[]

[tangye1234]

when I use ant Upload Component prop fileList: Array<UploadFile> as the initialValues of the form, the initial UploadFile[] cannot be assign to StoreValue, because the only supported array is StoreBaseValue[], not Store[]

So we need to change the typescript interface to:

export declare type StoreValue = StoreBaseValue | Store | StoreBaseValue[] | Store[];
export interface Store {
    [name: string]: StoreValue;
}

[tangye1234]

Meanwhile, when there is an undefined initialValue, it means that the input is not touched and have no value set on it. Maybe it is more reasonable that we should not set an undefined initial value, but when we came to some specific component like DatePicker, what value should be used instead when the date is not touched yet?

Hope there are some examples to demonstrate your design mode

[zombieJ]

Seems store should be any type since define it is meaningless.

ref: #36