Add headers in every connection method

[samchon]

Implementing #35, I understood that headers, it would be better to add to every connection methods. Therefore, not only WebConnector.connect() method, but also WorkerConnector.connect() and SharedWorkerConnector.connect() methods can use the headers instead of arugments.

Example

Previous WorkerConnector

export class WorkerConnector<Provider extends object>
{
    public compile(content: string, ...args: string[]): Promise<void>;
    public connect(jsFile: string, ...args: string[]): Promise<void>;
}

Future WorkerConnector

export class WorkerConnector<Provider extends object>
{
    public compile<Headers extends object>(content: string, headers: Headers): Promise<void>;
    public connect<Headers extends object>(jsFile: string, headers: Headers): Promise<void>;
}