support true numerical enums

[jon49]

I can do the following in TypeScript:

enum HttpStatusCode
{
    OK = 200,
    Unauthorized = 401
    ...
}

It would be nice if typson treated these enumeration as actual enumerations. I was thinking it could look for @type signature above the enum, e.g.,

/**
* @type integer
*/
enum HttpStatusCode
{
    OK = 200,
    Unauthorized = 401
    ...
}

and produce (per http://spacetelescope.github.io/understanding-json-schema/reference/generic.html):

{
type: 'integer'
enum: [200, 401]
}

Otherwise default to string enum

[low-ghost]

I was just about to file this issue. This is certainly the expected functionality and I'll go ahead and second this