Adding support for Interfaces implements and Interfaces extensions

[Allov]

Adding support for Interfaces implements and Interfaces extensions in the typescript templates.

Attempt to fix #98 .

It should cover cases like these:

Foo.cs

using System;
using TypeGen.Core.TypeAnnotations;

namespace foo
{
    [ExportTsClass]
    public class Foo : Bar, Car
    {
        public Car Car {get;set;}
        public string Far {get;set;}
    }

    public interface Bar : Far
    {

    }

    public interface Far
    {
        string Far {get;set;}
    }

    public interface Car
    {

    }
}

bar.ts

import { Far } from "./far";

export interface Bar extends Far {

}

car.ts

export interface Car {

}

far.ts

export interface Far {
    far: string;
}

foo.ts

import { Bar } from "./bar";
import { Far } from "./far";
import { Car } from "./car";

export class Foo implements Bar, Far, Car {
    car: Car;
    far: string;
}