Exclude error name from "IErrorObject"

[ejose19]

It's redundant to include error name in details (like we're not including other native Error properties there), so this PR excludes that property so classes extending Error have a cleaner output.

Repro code:

import { Logger } from "tslog";
const logger = new Logger();

class CustomError extends Error {
  constructor(message?: string) {
    super(message);
    this.name = "CustomError";
  }
}

logger.error(new CustomError("foo"));

Current output:

CustomError  foo
details:
{
  name: 'CustomError'
}
error stack:
...

Output after this PR:

CustomError  foo
error stack:
...

[terehov]

Thanks, looks quite handy. I just merged it